Heater and Thermistor Replacement

 

3D printers are very much a Rosane Rosanna Dana sort of thing. If it isn't something, its another. And one fix often leads to another problems or cascade of problems.

In this case, I updated my CR10 V2 printer to the Micro Swiss NG direct drive and all metal hot end. This cool new Direct Drive sits right on top of the hotend, extruder,  and gears are at a 45 degree angle to the printhead which lets things get closer together and means that the hot filament path is very short and has no bowden tube in it. This is great for soft materials like TPU. The previous version (which I put into my old Ender3) had a 2 inch piece of bowden between the extruder gears and the hot end. This one just goes extruder and metal all the way. 

What happened was this: I put the thing together (see the instructions Here) and the finished product had my control and fan wires in slightly different place than they had been with the origininal head. There was also the problem (though I didn't know at the time that it was a problem) that the wires didn't have anything to be secured to. No convenient place to put a wire tie to secure the wires in a safe way. 

Wires just sort of hanging out

This didn't appear to be a bad thing but it left the wires hanging in such a way that they were very susceptible to repeated motion stress. So after just a month or so of printing the constant back and forth right near the print head caused the small wires of the thermistor to break. And suddenly my machine didn't know what the printer head temperature was and it shut itself off. 

Crap.

So, I see I have to replace the thermistor and wires and since they are sold in pairs with the heater element, I may as well replace them to.  What I really need to do is fix the core problem of securing the wires near the extruder such that they don't just go and break themselves again. 

My first approach at this was to start designing a wire drag chain with secure locations at both sides for the X axis control wires. I spent a month or more on this and finally decided that the entire idea was wrong and that I should just have a good attach point built into the cowling that holds the extruder fans and install new wires and new wire cover.  Now THAT appears to have worked.

So I try running it again and I almost immediately get a bad nozzle clog. I can't clear it with any of the normal means. The clog is like, up inside the new NG extruder. DAMN. How am I going to clean that? I heat the thing up and then take off the few easy parts, that includes the fan case and the nozzle and the little heat ring dooker that goes from the extruder body to the hotend. It turns out that the little heat stop unit that goes from heaterblock to the extruder has a blockage. Since the job of this thing is to cool things off between the heatblock and the extruder, if there is a solid piece of previously melted plastic in there, it isn't going to come out by trying to force more filament through or by raising the temperature. The only way to get it out is to pull it out of the machine and take it to my work bench and heat it up with a little torch and push the blockage out. This isn't difficult to do, though you do want to be careful not to make things so hot that you char the plastic. When I read a bit about this it said to use a heatgun. I have one of those and must remember to use it next time. Easier to control the heat than with my little propane torch. 

Ok. So I get the clog out.

The other thing was that I did an email exchange with the Micro Swiss guys (they have great customer technical support) and was advised to pretty much do what I had done but also to make sure that my retraction settings on my build were set to something less than 1mm. Retraction is what the printer does when it has to jump over an empty space in the model. You don't want it dragging threads of plastic across, so you need to pull back on the filament to stop the pressure. When you use a bowden tube, you have a long ways from the extruder pushing and the hotend stopping. So you build up a long length of pressure and it takes a lot of retraction to stop the threading. I had my retraction set to 6mm. I thought I had changed it, but I had missed a few of my build templates. So I was retracting the hot filament right out of the hotend and into that little throat thing and the molten filmanet was cooling quickly there and making that terrible blockage.  So don't do that.

And now I do more prints. At this point I was still working on perfecting the cable chain that I eventually abandoned. Everything look screwy. Everything looked rough and lousy. Had I not cleared out the  blockage? I tried doing some prints with TPU. TPU is very soft and sticky and can often grab hold of little clogs and push them out. The TPU certainly seemed to be flowing well, but the prints still kept coming out all rough and lousy. What is UP?

An Older smooth one and the new rough (bad) one

A Rough PETG output. Ugly

I decided that I had to get serious. Have a plan. I made a list of things to do to completely clear out the entire filament flow path. Perhaps I have something caught in the depths of the Extruder and I just have to take it apart and clean it. I even made a spreadsheet of the things I would do and how I would do them. But it just seems like the flow was working so well. I was getting terrible threading though, with all filaments. 

The internets suggested that to stop threading I could try a lower temperature. 

So I got a threading test tower (just a few fingers sticking up in the air) and used the Curo advanced settings to change the temperature on each segment of the tower as it went up. I tried this on PETG and PLA and got OK results with sort of low temperatures. Then I tried it on TPU. TPU temp is supposed to be 215C. I swept from 215 to 195. 20 degrees of sweep. And I was still getting terrible threading. 

TPU Temperature Sweep

Was everything just too hot?

And then it struck me. I had put in a new heater element and a new Thermistor. I really didn't know if the new thermistor was the same as the old one or what sorts of tollerances there may be on different thermistors. I bought a cheap Multi-meter that had a little wire temperature probe and I pulled off the nozzle and stuck the temperature sensor up there and did a test.

I found that my actual temperature was 20C higher than the temperature I was setting. Holy cow, no wonder everything looked like shit. I tried just sweeping even lower. From 195 to 180. Now things were looking better. I wasn't getting that Rough surface effect, but I was still getting stringing. Almost like I didn't have retraction turned on at all. I looked at my settings and though I had retraction set to 1, I did NOT have it enabled. dammit. 

I enabled retraction, ran at the artificial low settings, and Bam, things suddenly looked OK. 

I was thinking about just making a paper table that told me to do things like "If you want to run at 215, set you temperature to 193", but that  was not very satisfying. So I figure out how to put a new thermistor temperature table into the Merlin firmware and recompiled and reloaded the entire thing. Only took me a day and wouldn't have taken that long  except for that you typo that almost melted my printer during testing. (if you want to do this, there are plenty of tutorials on the web. Or ask me to write one JUST FOR YOU. I would it because I would be so glad that someone read my blog.).

And so, there you have it. I think I now have a working printer that has the right temperature, has a great direct drive extruder, has new pretty blue cable stocking, and has a customer cable attachment shroud that looks great. See the pictures.

Now lets just see if this thing will run for a few months without breaking.

3D Printer Primer

This string of posts is meant as a starter guide for 3D printer. Many of the subjects will be pointers to empty pages until such time as I go back and fill them in. Or you can write them for me and let me know the URL…

Picking A Printer:

My experience has been with the simple open source printers like that sold by Creality. As such I will be concentrating on that ilk. I have a CR10 (V2) and a Ender3. I have modified both of my printers to be direct drive. These printers are in the $200-$400 dollar range and can print things up to about 300mm (1 foot) cubed. (The ender is 230mm). I am not sure it makes sense to get extruded plastic deposition printer that is much larger than this. Printing something full size takes several days and the probability that something will go wrong and ruin your print grows rapidly with print time.  Of course, you may want to print something that is small in volume but long (like an arrow) and that is what I usually use the larger printers for. (well, I don’t actually print arrows, that would be silly).

Printer Technology:

These open source printers are basically robot arm controlled glue guns. They run the tiny glue gun around in a controlled manner and slowly build up a 3D object one layer at a time. They have 3 axis controls; X,Y, and Z. The ‘hot end’ (the glue gun) is mounted to the X axis. This goes back and forth on a belt that is inside the horizontal arm on the printer. The Y axis is the bed of the printer. The bed moves in and out also on a belt. The Z axis is up and down. This is achieved by raising and lowering the X axis bar. This is controlled by a screw. All of the axis are driven by stepper motors that are controlled by an Inguino based micro controller that is part of the printer. 

The Hot End has a thermister (a temperature sensitive resistor) that allows precise control of the temperature of the hot end. This is important because different plastic filaments have different melting points. There are also a couple of fans that are necessary to help the deposited plastic cool quickly and to protect the parts surrounding the heating element for over heating. 

Plastic Filament is pushed through the hot end by the Extruder. The Extruder is a set of tooth studded wheels that grip the filament and push it along using the power of yet another stepping motor. The original (and lower cost) systems have this extruder mounted in a fixed position on the X-axis bar. A plastic tube (called a bowden tube) carries the plastic from the extruder to the hot end. This tube is bundled up with the control wires going to the hot end and is a common failure point on this type of printer. My printers have been upgraded to ‘Direct Drive’. This puts the extruder motor on the moving part directly above the hot end. The going part about this is that it eliminate ‘most’ of the bowden tube and so makes a more precise plastic delivery path. This in turn allows for the use of softer plastics, such as TPU. It is hard to print soft plastic with a bowden tube because the soft material compresses in the tube and just won’t push through.  The down side of a direct drive is that the heavy extruder and stepper engine is now ON the X axis. This weight makes more inertia on the moving end which means it is harder to start and stop. This may mean that you have to print slower that a bowden tube printer. Also, using current technologies, the direct drives are sort of expensive. 

Setting Up Your  Printer.

Where to Locate the printer. The printer really wants to run at ‘Room Temperature’. This is around 20C (official engineering Room Temperature is 25C).  Too Cold and the filament won’t stick to itself. Too hot and the controller will malfunction and the filament will not stick to itself. 

So printing inside is nice. HOWEVER, printing makes fumes and dust which is not good to be inhaling, so the printer should not be in a sleeping space or an eating space.  I think thing is to have the printer out in the garage. During the spring and fall, you can just print and no problem. During the winter you may need a simple enclosure that you can heat a little. An enclosure can be as simple as big cardboard box. You can also get nice en

I assume that you have an assembled and operational printer. If you have just bought a new one and it came unassembled in a box I encourage you to 1) Read The Instructions 2) Watch a Youtube video on the assembly 3) Read the Instructions again.  4) Take your time.

Level The Bed:

The printers that I have do NOT have automatic bed leveling. I tried using it and it didn’t work so well. I may have had a faulty bed sensor since all of the cool guys with web sites seem to think that these devices (ABL, automatic bed leveling) work great. I use the manual mesh method. In this method, every so often, when something about your printer changes (like a new nozzle) you need to do a manual leveling process. This involves going through the control screen on the  printer and finding the manual leveling command. Then the printer will run the head around on the build plate and you will turn the control to adjust the height of the head at each position to be 1 piece of paper thickness above the plate. I just have a piece of paper I stick between the two and turn the dial until the head grabs the paper just a little bit. You set 9 positions and then the printer will remember the differences and so be able to adjust for non-flat tables. This works really well though you do have to remember to put the “use the Mesh Leveler” command into the gcode for the print.

You will also have to adjust the global height of the print head. You can do this at the beginning of each print or you can set a global value in the “bed leveling” menu screen.

Load The Filament

Direct Drive: To load the filament in a direct drive follow this procedure:

1. Trim the end of the filament. Ideally this would be shaped like a sharpened pencil such that the filament will easy fit into the tubes it has to pass through, however it is hard to get that shape. I usually compromise by using the filament cutting pliers (the blue handled ones that came with the printer) to make two sharp cuts and make a sort of blade shaped tip. 2 cuts is enough. 3 is better. 4 is probably too many, 1 is often not enough. 
2. Preheat the hot end to the temperature appropriate for your filament. Usually 200C for PLA.
3. If you are near the end of roll of filament, and it is sort of bent coming off the reel, you should try and straight out the last couple of inches by bending the filament straight. 
4. Push the filament into the tube until it makes contact with the direct drive teeth.
5. Use the printer control screen to advance the Extruder. For the Ender3 I have found that you need to advance it 110mm to get the filament to start to come out.
6. If the filament doesn’t come out the nozzle, something is wrong. Check that your path is clear and try the instructions again.

Print the Model

If you don’t have a gcode file to print, go look at the directions for ‘Slicing Your Model’. If you have GCODE, you need to put it on a SD-Card and put that SD-Card into the printer. Now you can navigate the printer screen to ‘Print From SD CARD’, find your model file name and hit go. For the first couple of models you should watch this happen.

1. Bed will heat. For PLA this is 50C. Be careful, 50C is hot.
2. The Hot End will Heat. Hot end heat is 220C. This is very hot and will burn you quick. Keep your hands away from the front end.
3. The printer will HOME. This involves moving the AXIS controls until the print head hits the end stop switches. This allows the printer to figure out the position of the head and arms (i.e. at 0,0,0 which is ‘home’).
4. Now the printer will start printing with a wipe and a border around the print. Until you KNOW that things are going to be working well, you should watch the printing. 2 presses of the control button at this point will put the printer into ‘baby step’ mode. Now you can actively change the base height of the print head to insure that the first layer is sticking to the bed. This is CRITICAL!!. The first layer sticking is one of the most important parts of the process. Adjust the height of the head such that the filament is flowing but the slightly flat and sticking to the bed. You should be able to touch the filament on the bed (don’t touch the hotend!!) and it should not move. If the head is too low, the extruder will make a stranger noise as it slips. That is bad. If you can’t find a position that works for the entire outline of the first layer, then your bed is probably not level enough to print. In this case you must do the leveling again.

Removing the Printed Model from the Bed

If you have a textured bed, which is the default on most Creality printer beds, and you have your head tracking the right height, you are going to print a model with really good adhesion to the bed. Really good. It could even be just a little TOO good. In that case you may find that the model is sticking so well that you just can’t get it off of the bed. Don’t Panic. Do NOT try and force the model off. You are capable of pulling so hard that you will actually pull the texture surface off of the bed and ruin it. Bad 3D Printer Person! 

So what do you do?

1. Wait. The Bed and the Model have different coefficients of thermal expansion. This means they change size with heat, but at different rates. As they cool, one shrinks faster than the other (I think the plastic shrinks faster) and so they will naturally pull themselves apart as they cool. This can take awhile. It can take 30 minutes. 
2. If you can pry up a little corner or side, sort or break the suction, the entire thing may pop off. Do this with a razor or a thin box cutter blade. Put the blade flat against the bed and just slide it a little into the bottom edge of the model. Don’t force it. If it doesn’t work, it doesn’t work,
3. It is nice to have a spray bottle of rubbing alcohol on hand. I use it to clean my bed in between prints. You can also use it to cool the bad more and help de-attach the model print. Just spray the bed along the edges of the print and wait. Sometimes you can hear the model pop off. 
4. If none of this works, you have have to resort to removing the bed from the printer (it is only held on with a few clips) and take it too the sink and run cold water over it. This is really the last resort. While you are there, give your bed a good washing and don’t use it again until it is completely dry.

Removing The Filament

If you want to change the filament to a different color, or you just run out of the roll, you will have to remove the current filament. For a direct Drive follow this procedure:

1. Preheat the hot end to the right temperature for the filament that is in the printer.
2. Advance the filament 10mm.
3. Retract the filament 10mm.
4. Immediately release the pressure using the bar on the extruder and pull the filament out from the reel end.
5. If you are putting in a new or different roll, make sure the hot end is heated to the right temp and follow the instructions for loading filament.

Common Problems and Solutions:

Filament doesn’t stick to the build plate.

(Also Called “The First Layer Problem”)

One of the hardest things is to get your first layer dialed in and working properly. Once you have the first layer going, the rest will print out with high probability. Here are some things you can do if your first layer just isn’t sticking.

1. Level the Bed
2. Clean the Bed. This is especially true if you are using the shinny glass side of your print  bed. You can take the bed into the sink and clean it with  soap and warm water. You can also clean it in place using a paper towel and rubbing alcohol.
3. Print using a mat. If your model only has a couple of attach points (Like you are printing a standing figurine) you may find it necessary to print using the mat setting. This will print few layers of filament stacked under the model and the model will then adhere to this mat. This can also be an effective way to get around problems with your print bed not being level enough. The problem with the Mat is that it gives the bottom of your print a kind of ugly rought look. Of course, this doesn’t matter on many models. (Like a standing figurine).
4. Use ‘Baby Steps’ to micro adjust the height of the head during print startup.
5. Spray Hairspray on the bed before printing heatup. This works really good for PETG.
6. Put blue tape down for an adhere layer. I used to do this all of the time but I have found that using a nice clean glass bed and hairspray works most all of the time and is easier to maintain.
7. You can also get a removable bulid plate cover that clips on to your build plate and will give extremely good adhesion for 10 or 20 prints. You can also flex these sheets to get the print off. 

Filament Will Not Flow

1. Clogged Nozzle
1. Try removing the filament and re-loading. This will often clear a blockage.
2. If that doesn’t work, try replacing the nozzle. 
3. Heat the Nozzle to filament  temperature.
4. Use the (6mm?) socket to remove the nozzle. Remember it is HOT.
5. Install the new nozzle. Hand tighten only. You may need a pair of pliers to hold the hold end still when tightening the nozzle.
2. Clogged path. This is harder. It probably will involve taking the entire extruder-hotend unit apart. This is beyond the scope of these notes.

Min Temp Warning

The printer has a safety feature, if the temperature sensor on the bed or the hot  end reports a temperature that is too low (below 5C usually) the printer assumes that the sensor is broken, which is bad, and it will refuse to operate. It will Turn off.  This problem is usually caused by one of two things:

1. The Sensor Wire is broken. This can happen after many prints because of repetitive motion bending the wire back and forth. The wire needs to be replaced.  ADD MORE INSTRUCTIONS HERE
2. The Printer is TOO COLD. This happens to me in the winter if my printer is in the garage. You need to heat the printer up. This requires either bringing the printer inside or putting the printer in an enclosure that you can heat with a light bulb or something like that. 

Print Layers don’t Adhere to each other:

A few things can make the print turn out all wiry and the layers not sticking to each other.

1. Not enough filament. The nozzle is clogged. Go fix that.
2. The Room temperature of the printer is too low. Anything below around 12C is probably not going to work well for any filament type.  You need an enclosure or print inside. 

Tools and Utilities.

Thingiverse. 

There are a couple of websites that have collections of designs that other people have made that you can download, prepare for your printer, and print. I like thingiverse. Have a look there.

A Slicer.   

The Cura slicer is a free to download slicer that is used by many. A slicer takes a design in STL and prepares it for printing on your printer. It slices it into the right size slices (based on your nozzle size) and sets up things like the mesh leveling and needed supports and generates a series of printer instructions called GCODE. You put the GCODE file on your SD-CARD and then you can print the design.

Design Software. 

When you are ready to really have fun, you will need something that will allow you to either design your own models or make some little modifications to things that you get off the web. For instance, I have used design software to put my name on a whistle. I have also used design software to completely design a G-Scale train car. 

I recommend starting with a simple online program called TinkerCad. It is easy to use and you can figure it out yourself. Later, when you are ready to do something really complex, you can decide on a real CAD program or a parametric program like OpenSCAD. (I Like OpenSCAD. I think that is what it is called).

There are some much more complex Computer Aided Design (CAD) programs out there that do everything from Computer Board Layout to Designing a House and some of them now also support the rendering of 3D models. There is one from Google and there is a big one called AutoCAD. I have tried the Google one out but it just took too long to get anything going and I gave up. OpenSCAD is like writing a simple computer program and I found it easy to use. It is nice because it is ‘parametric’. That is, you can enter computer program variables for the size of things instead of actual numbers and then go back in and fill in the sizes later. Why is that good? Lets say you are making a socket wrench. Instead of saying the socket size is 3/4inch (or 20mm) you could just say it is WRENCHSIZE. Then later, when you know what you want, you way WRENCHSIZE=20. This would mean that one design would let you specify your entire socket wrench set, just change the variable value!!

Printer Controller.

Though you printer has an embedded controller (an Inguino) and it is running a simple program to read GCODE and control the printer, there is a lot of function that it doesn’t provide that you may want to have. For instance? You may want to control and monitor your printer via your LAN. I use a controller called Octipi that runs on a Raspberry PI micro computer. It acts as a website server and generates a website that lets me monitor my printer, submit print jobs, see the printer temperature, and even get a camera view of the print in progress. This is nice when your printer is out in the 10C shed and you want to check your print status every hour or so to make sure the thing hasn’t gone to seed.

Though Octipi is free and you can download and use it for free, the Raspberry PI is not free. As of this writing, it is very hard to get an RPI because of the computer chip shortages. You need something at least as good as a RPI 3A+. A RPI4 would work fine, but they are twice as expensive (during normal times) as the 3s. I think a $20 RPI Zero 2 would work but I haven’t had a chance to try one yet. I did try an old RPI 1 and it just wasn’t fast enough to reliably send the GCODE instructions to the printer. 

Once you have Octiprint loaded, you can Design, Splice, Print, and monitor the print all from the same computer. 

The Importance of a Clean Bowden Tube

The Importance of a Clean Bowden Tube

There is a lot of advice out there on the internet for 3D printer fans. Not the kind that blow, the kind that are people. And don't even go there.


Anyway, the advice is copious and varied and often misleading, obsolete, or just wrong. So how can you tell if it is good advice? One way is to see if you can get several authors to give more or less the same advice. Another is to watch a video of the advisor actually doing the action. One last thing (and this applies to the obsolete bit) is to try and figure out if the advice being given is either very recent or  applies directly to the model thing you are working on (for instance, can you see in the video that the parts being serviced look like the parts on your machine).

One common issue that EVERYONE talks about is nozzle clogs. Also sometimes referred to as Hot End Clogs or perhaps as God Damn Fraking Clogs (GDFC).


Clogs seem to occur at joints where various components of the filament feeding system connect to one  another. They also occur in the constricted areas of the nozzle where tiny impurities in the filament can get stuck and accumulate enough to form a partial blockage. You usually know you have something wrong when your prints start to come out weak. They look OK (perhaps) but when you flex them you find that they appear to be made of cotton candy instead of plastic.

Now comes the part where advice got me into trouble. I am watching this video about the printer I just got (The Ender-3 from Creality) and it shows a common problem where the bowden tube connectors near the extruder stepper engine is not grabbing the bowden tube securely enough. Because of this, each time the Extruder Stepper retracts a little (which is often done when moving the head across a No Print area) the connector moves. This movement implies the bowden tube is moving. So instead of retracting the filament, we are just flexing the bowden tube some. Non Ideal.

And now you are saying, "What is he talking about? What is a Bowden Tube?"

The White tube coming from the back left
to the blue extruder on the left if the Bowden. 
Filament roll is off picture left.

On the open license printers, the filament extruder comes in 2 distinct parts, The Extruder Stepper motor (which pushes a carefully measured amount of filament through the hot end) and the Hot End (which is essentially a precision glue gun). On many machines these two parts connect pretty much directly to each other (this is how it was on my original M3D Mini). On the Ender 3, however, the extruder-stepper motor is fixed in place over on one of the side supports and the Hot End is moving around on the X axis Arm. Between  these two parts is a plastic Tube that channels the still hard plastic filament from the Stepper to the Hot End. This is the Bowden tube. One my Ender 3 it is about a foot long.

So anyway, the advice says that any play in the tubing is a bad thing for print precision and you should fix this situation by getting a high quality Bowden Tube and tube connectors. They are like $7.00 on Amazon. So I got them.

Now, one would think that all one need do is to pull off the old parts and stick in the new parts but this is where I ran into problems. The part of the bowden tube that sticks into the hot end HAS TO push up right against the nozzle. Any space in between these parts leaves a place for hot filament to sneak into and cause blockage and bad prints. This becomes hard to work with because the way the bowden tube latching mechanism works is that you press the tube through the connector and then pull back a little to lock it. This pulling back creates a Gap !!

And my advice guy didn't tell me about this.
This meant that not only were my next many prints bad, but I didn't realize the problem and so was doing normal clog clearing things (like a cold pull) and that was having no impact.

So. I went and did more research. I found a guy warning about the distance between the bowden tube and the hot nozzle. He claims it often comes from the factory with this space problem. How to fix it? Pull off the nozzle and insert the tube and visually confirm that the tube sticks just the tiniest bit out in the threaded area of the nozzle. Now when you put the nozzle back in, it will abut the tube and you won't get leaks.

See what I just did there? I gave you advice without the appropriate warnings:

1. Never remove or tighten your nozzle unless you have preheated the head to PLA (200C)
1. this turns out to be a biggie. Who Knew?
2. Don't put your skin against anything preheated to 200C.
1. This is an even bigger biggie. Especially for us Americans used to Fahrenheit.
3. Make sure the Hot End track is cleared of Gunk before you put in the Tube and Nozzle.
1. How? I did it by taking a small extra piece of tube (6 inches) and pushing it all the way through the hot end with the end HOT. It pushed out a huge glob of gunk.
2. Be careful, your piece of tube will heat up quickly. Perhaps wear gloves for this.

Want some more Bowden Tube Advice?

Every once in a while you will get a hunk of plastic stuck in the tube. Right at the end where the tube is hot and the filament melted in it and made a clog. You usually get rid of this by cutting off the end. Many people say, don't snip it with your filament cutters as this will bend the tubing. Other people just go ahead and clip it and don't seem a bit concerned. A third guy says to ether buy the special Bowden Tube cutter, or use a very sharp cutting tool, like razor. That is what I did, I used the blade of a box cutter. 

Does having the new Bowden Tube and the new attachment mechanisms that don't slide matter? 

Maybe.

A little.

But certainly not worth the hassle.

On the other hand. Look how much I learned.....

And now, future Me, gives some even more useful information. Go onto Thingiverse and look around for some Your Machine Specific hot end additions (try here). Essentially, there are measurement devices (yes, you could use a tape measure) and a little gasket that allow you to cut a short piece of bowden tube material and fit it into you printer between the nozzle and the bowden tube attachment fitting. This provides a specifically measured piece of tubing such that you won't ever have that leaking gap again. Work great. Less filling. 

I also have the answer to the question of "Why have  Bowden tube at all?". That is, why not put the extruder right at the hot end and avoid that long path? It is a tradeoff. Putting the extruder right at the hot end (which is called a direct drive extruder) does make for really nice well constrained filament path. It allows you to print flexible, like TPU, and it seems to give very exact control over PETG and PLA (which can make less threading and such). However, it puts more weight and strain out on your moving arms. Which means you may need to move your arms Slower to avoid inertia fracking with you. The direct drive mechanism is also a bit harder to load.  However, that said, I put a direct drive onto my Ender-3 and I love it. (I still have the Bowden on my larger CR10).

Even more Future Me says: Hey, I just put the Micro Swiss NG Direct Drive Extruder on to my CR10 V2 and it appears to work great. The advice to slow the X-axis moves down a little seems to be needed, however.

Adding a MicroSwiss NG Direct Drive Extruder to a CR10 V2

I really like the Micro Swiss Direct Drive Extruders. I got their original for my Ender3 and it was great. It made my prints look a little better and seemed to have better registration and it allowed me to print with softer filaments. In particular, it let me make things from TPU which is really powerful. There are many things that become possible with TPU. For instance, I could print a top for my water bottle with the waterproof washer integrated into the design. When I was printing these things with PLA or PETG I had to use an external washer or they would leak.

My problem was that I really wanted to be able to have just one printer, and my Ender3 is too small to be my only printer. I wanted the direct drive capability on my CR10-V2.  Micro Swiss did not have a conversion kit for the V2, however. They also had this new unit out called the NG which has the extruder set at an angle to the hot end. This evidently provides for a shorter push path (less clogs) and also takes up less room above the hot end, which means you don't hit the top of the Z-direction quite so fast. 

So I waited for them to have a conversion kit for the CR10-V2. They released something just recently for most of the CR10s and Enders, but not for the V2. Sad face.

I contacted there customer support and got a very quick and accurate and helpful response (thanks Paul!!). It said that they had not yet released a complete V2 kit but provided additional instructions (and parts to print) that I could use to figure it out myself.

Challenge Accepted !!

What follows here assumes that you have the current (11/2/2022) NG CR10 kit from Micro Swiss along with the directions they provide AND the extra directions their customer support provides (which I will duplicate some of here). Go Read The Original Instructions. Here is the LINK. No excuses.

The (extremely good) supplemental instructions from Micro Swiss Customer Support that I received are at the end of this blog.

Ready to start?

Print Required Parts

I am going to assume that the only printer you have is the CR10 V2. This means that the first step is to print the replacement fan shroud you are going to need. Here is the one they recommend out on Thingiverse <LINK>. I printed this in PETG and that seems to work fine. I guess I would not recommend PLA, I am afraid it will sag from local heat. Print this with support On BuildPlate Only.  If you try and print it with support everywhere you will get a mess that you can't pull part non-destructively. 

There is also a little part that lets you mount the filament guide tube close to the filament run-out sensor (where the current extruder sits). You should print that too. 

The main difference in this new shroud and the one the kit comes with is the hole for the part fan. OH, and the new shroud is purple. 

The new shroud has a mount for a BLtouch. I don't use a BLtouch because I find that the manual mesh method works fine and I had found the auto bed leveling to be untrustworthy. I will no doubt have to go back and try that again sometime. I suspect that my sensor was faulty.

Disassemble CR10 V2

Getting the shroud assembly off of the V2 is not so simple. There are multiple bolts to be removed from the back of the mount plate. I am assuming that we want to put all of these parts aside and save them in case we don't like the Direct Drive and want to revert. It is helpful to take pictures as you go...

At this point, you can get the two fans off. You can save the screws but I don't think they will help you much attaching the fans to the new printed shroud since these screws are not self tapping.

Now, in order to get the heater and the thermistor out of the shroud, you need to find the 3 allen wrench bolts that hold the two halves of the shroud together. Take them out and crack the shroud open and now you can get to the hot end and remove the heater and the thermistor. A note here, I had a hell of a time getting my thermistor out. I think it was a little glued in. So be careful there.

Remove Roller Plate

This plate comes off pretty easy.  The instructions from Micro Swiss work for this. Note that you are not going to be able to reuse the belt because it is too short.  You also don't need to save anything except the roller wheels. All of the other hardware comes in the NG kit.

Remove Old Extruder

The only real trick here is that you need to remove the tension arm from the extruder first in order to get access to the bolts that hold the extruder to the mounting plate.  Just take it all off. There is nothing here that you are going to reuse. The bolts don't help you since they need something to bolt to.

Attach the NG Extruder and plate to the X-axis arm

I think this is the hardest part of the modification. Not so much the attaching the plate, that is pretty easy. The hard part is getting the new belt on and sized. You did order some new belt as per the instructions, right? To bad they didn't make the plate half an inch longer, then you wouldn't need to do this. (Note: It occurs to me that you may be able to do something really simple like using a short piece of fishing line or other small line to do a little extension on the original belt. The side facing away from the Motor doesn't need to have teeth on it close to the extruder. )

The instructions that I got said to make a loop of the toothed belt and hold that loop in place with zip ties, then just hook the loops you made over the slots in the plate. That doesn't work. You can't make the loops small enough that they don't get sucked into the X stepper motor. And that isn't good. How do I know this, you may ask? 

Anyway, what I found works well is to duplicate the existing CR10 V2 solution of having a stop on the ends of the belt. The stop on the original is a metal staple thing. I found that a zip tie cinched in hard at the end will work just as well. Now you need to get this entire thing sized right and tightened. HINT: Loosen the currently tightening plate that is holding the belt taunt. That is on the X arm at the opposite end from the X stepper motor. Now you can size the belt and then tighten it up by cinching out that arm.

This method of belt attachment DOES NOT WORK

This is a good shot of what doesn't work. 
It just sticks out too far, mainly on the side
close to the X Stepper Motor.

Attach the Hot End.

This is pretty much exactly as the Micro Swiss Instructions describe. Do that.

Assemble the New Shroud

We are now going to put the fans and such onto the newly printed (and perhaps purple) shroud. First, remove the kit included (and probably black) shroud from the NG extruder. We need the 2 screws that hold it in place. Put them into the appropriate and matching holes on your purple shroud (I am just going to call it that to avoid confusion). You are not attaching it to anything yet, but later you will be glad that these screws are already set and waiting in the holes. 

Now you need to attach the two fans. Note that the instructions in the KIT don't work for this as the screws don't fit as directed. Well, the 4 big self setting screws in the KIT for the fans will work for the main body fan. For the part fan you will have to find your own screws that fit. (I just went through my bunch of extra 3D printer fans until I found some that fit).

(Update:I think you want M2.5 x 20 bolt and nut here).

Sorry, I forget where I got these screws

Attach Shroud to NG Extruder Body

It is a little hard to push the fan and heater wires out of the way and get the purple shroud to mate in against the NG extruder. Take your time. This is what makes this hobby fun. Keep saying that to yourself.

If you are like me, this is where you find out that you routed half of the wires under the X-axis arm instead of over it and much cursing ensues.

Hook Up The Control Wires.

The instructions that I got had a lot of detail on how you had to switch the wires on their Extruder Extension cable to make the extruder turn in the right direction. I have 2 things to say about that:

1. If you are doing this NG Extruder hardware mod, there is a good chance you are also burning new firmware into your unit. The latest firmware is certainly better than the stock firmware.  If this is the case, you can do this wire switch with on un-comment in the Marlin code (though I used and recommend the TH3D version).
2. I found that I did not need a wire switch. Things worked just fine with the original direction (yes, this means I switched it in software and then when it didn't work I switched it back again).
3. UPDATE: On taking my CR10 apart to fix some bad wires I find there is a little adapter cable that is about 5 inches long and runs from the cable housing near the where the X-axis cable plugs into the printer out to this extruder control. This little adapter cable has the middle 2 wires switched. That appears to be its purpose in life. Go figure.

By the way, the latest firmware also lets you specify the estep of 400 which is important to get the NG extruder to push the filament out at the proper rate.  The instructions say to use a GCODE override which they provide. That is fine and works fine, but if you put it in your Firmware, it will still be there a year from now when you update to an auto-probe or linear rail or whatever else is cool in a year.

Attach the little guide Thingee

Micro Swiss provides the gcode for this little guide thing that mounts where the old extruder used to be. You will have to find your own screws to hold it down. Also, it has a little tube holder that slides into it. There is an extra one in the KIT you can use.

Is that everything?

I am still having problems printing with TPU. I suspect that my two culprits are: A) Filament Spool is too hard to turn 2) I don't have the NG tension spring adjust tight enough for TPU. Still working that but something to be aware of.

The NG loads and unloads filament like a dream using the Micro Swiss recommended methods.

LOAD: 

1. Heat Hot End
2.  Feed filament up to extruder teeth
3. Start Extruder (do like an extrude of 100mm)
4. Give the filament a little push and let the extruder take it.

UNLOAD:

1. Heat Hot End
2.  using an extruder command to extrude some (say 40mm)
3. Before end of this extrusion, hit the pressure release lever on the NG and pull out the filament by hand from the spool side.

Because of the added mass on the X-axis, I think it may be important to limit the max speed of the X-axis stepper motor. I found this especially necessary during manual Mesh setting, but I have also noticed it during some aspects of a print. Perhaps limit travel rate in the slicer.

Additional CR10 V2 Instructions from the Micro Swiss Customer Support Team

The following was the supplemental instructions I received from Micro Swiss. I hope they don't mind that I reproduced them here.

If your CR-10 V2 does not have a bed leveling probe, then it should be pretty easy to rig our current CR-10/Ender-3 NG Extruder to your printer. You would just need to make these parts/modifications:
- 3D print a fan shroud
- 3D print a PTFE Bracket 
- New GT2 Belt
- Small Zip ties
- Modify the provided Extension Cable

If your printer has a bed leveling probe, then it will definitely need custom firmware with updated Home Offsets and Nozzle Probe Offsets. In that case, the motor direction can also be changed in the firmware instead of modifying the extension cable as detailed below.


Here are more detailed explanations for each of those bullet points.

Fan Shroud
- Needs a custom 3D printed fan shroud for 5015 part cooling fan
https://www.thingiverse.com/thing:5371792

PTFE Guide Tube Bracket
- Print the attached PTFE Bracket (MSDD_PTFE_Bracket_CR10V2.stl)
Instead of feeding the filament into a short PTFE tube on top of the NG Extruder, you will need to connect the original long Bowden tube to the top of the NG Extruder and connect the back end to a printed bracket which will sit in place of the original extruder. This bracket will align the long PTFE guide tube with the CR-10 V2 Filament Runout Sensor.
I've attached a bracket STL file that can be used to hold the PTFE guide tube in front of the CR-10 V2 filament runout sensor. The NG Extruder comes with a spare Bowden Fitting that can be used to attach the filament guide tube to this 3D-printed PTFE Bracket. Also, here is a link for spare Bowden Fittings if needed.
https://store.micro-swiss.com/collections/spare-parts/products/replacement-bowden-collets-for-micro-swiss-cr10-hotend-kit-set-of-3

Belt
-  X-axis belt will be too short and will need to be replaced. To purchase a new belt, search Amazon or Google for "GT2 Belt", they come in long spools. Then use zip-ties to clamp the ends of the belt together as shown in the attached image.

Zip Ties
- You will need four small zip ties to clamp the two ends of the GT2 belt together as shown in the attached image.


Modify the Extension Cable
- You will need to modify the spin direction of the E stepper motor. The NG Extruder comes with a cable that has the specific pinout required to convert a CR-10 to work with the NG LDO motor. When this NG Extension cable is installed on the CR-10 V2, the motor will spin the wrong way. This can be corrected by either modifying the firmware or by modifying the way the stepper motor extension cable is wired. 
 
To check the wiring pinout of the extension cable, connect the two ends of the extension cable together and that will show you how each wire is connected. To change the spin direction, the wires on one side of the connector would need to be swapped around so it looks like a mirrored version of the original pinout. Here is an example to better explain what that means.

Generic Extension Cable Pinout
Pin 1 > Pin 1
Pin 2 > Pin 2
Pin 3 > Pin 3
Pin 4 > Pin 4
A generic extension cable does not change the pinout of the wiring, so each wire will connect back to itself when you connect the two ends of the extension cable together.

Generic Extension Cable Pinout (Mirrored)
Pin 1 > Pin 4
Pin 2 > Pin 3
Pin 3 > Pin 2
Pin 4 > Pin 1

A mirrored pinout looks as if one of the connectors was just flipped 180 degrees. This type of pinout will cause the motor to spin the other way.


The pinout above is of a simple stepper motor extension cable to help explain the concept. The NG Extension Cable has a unique pinout that is required for installing the custom LDO stepper motor onto a Creality printer. The wires will need to be kept in that order, just flipped to the other side of the connector to create that mirrored pinout, in order to change the motor direction.

NG Extension Cable Pinout 
Pin 1 > Pin 1
Pin 2 > Pin 3
Pin 3 > Pin 2
Pin 4 > Pin 4
This is the cable we include with the kit, which basically just has the center two wires swapped around when compared to a generic extension cable. This the the pinout that is required for regular CR-10 and Ender-3 printers, but will cause the motor to spin the wrong way on a CR-10 V2 or V3.


NG Extension Cable Pinout (Mirrored)
Pin 1 > Pin 4
Pin 2 > Pin 2
Pin 3 > Pin 3
Pin 4 > Pin 1
This is the extension cable pinout you would need if attempting to install the NG Extruder onto a CR-10 V2 printer. This can be made by modifying the Extension cable included with the NG kit.

So you want your RPI to be a WIFI Hotspot?

 Man, there are a lot of articles out there on how to turn your RPI into a hotspot. Or just how to communicate with your RPI through WIFI. Or how to raise poodles.

I am not going to duplicate all of that work, but I will say that I tried an awful lot of "methods" to make my RPI3 be a hotspot and all of them worked just about as well as the rules on poodles.

Until I searched for something like "Script that does WIFI setup automatically"

Then I got pointed to a guy that eventually pointed me to what seems to be a good (and working) answer.

It is called RaspAP

in particular Raspap-webgui.

main paige is here:https://github.com/RaspAP/raspap-webgui/blob/master/README.md

don't forget to take the first instruction of setting your country mode and such on your RPI. that was key for me. Everything else I just accepted whatever RaspAp wanted to do to me.

My ultimate goal was to get standalone PLEX service running on that baby. The secret there is to go find the way to turn off local authentication:

Ok. This is mainly a note to future me, so if you are not me and didn't read this, don't feel bad.

God, Cows, And Intelligent Design

My recent work with 3D printing has had me thinking about the arguments between Evolution and Intelligent design. Leaving aside Science and Rational Thought for a moment and putting equal weight on the concepts of Evolution and Intelligent design I say, hey, let's take a look at a recent 3D model I have been designing (I claim intelligently).

I have been working on this project for years. Much like God let the universe swirl around for a few billion years before he got to work on 'Life'.  My project is to put programmable flashing Christmas lights on my G-Scale home train. So it would go around the tree and blink pretty programmable patterns. The problem is hooking the lights to the trains in a way that doesn't look all schlocky. I had tried with wood. Ugly. And didn't work. The lights kept falling off. And I need a way to hide the solder joints. Then I got a 3D printer. It was a great start. But it was sort of small. Two many pieces had to be hooked together. And it still didn't look so hot. Then I got a bigger printer. And I had this idea of how to put the light holders around the top of the car as a sort of raised roof technology. It would look like an original part of the car. And then I started to design that.

I made a lot of scrap plastic on the way.

Each time I printed it I would try something different and better and my design sort of.... evolved... toward the right design. It was intelligent design, but with evolution !!

Perhaps it was like that with God and Cows. God was out creating Cows and he would print one up (using a previous cow's self replicating mechanism) with a few minor tweaks from the last print. He would take a look at it, see how it mooed, see if there were any gaps he didn't expect and that everything fit nicely. Perhaps he would notice something that would be better in a slightly different shade of brown. So he would tweak the gcode (called DNA in COWS) and have the latest sample print him the next generation. And so forth. Eventually he had something that he thought made a really good cow and he was pleased with himself. Then he sat back and thought, "How in the hell am I ever going to get programmable Christmas Lights hung on this puppy?".


get intelligent design guys and evolution guys together using 3D printing.

Gee, that isn't quite what I had in mind when I thought "Cow".

Meta Hobby

3D printing, for the average joe, is considered a hobby. But I maintain that it isn't so much a hobby as a meta-hobby. That is, it is a hobby that helps you do hobbies. To make it even better,  the main hobby that it helps you do is 3D printing. How Self-Referential !!

For instance, let's take a look at my small 3D printer, a 200mm standard design Ender3 from CReality. I believe it was selling for $250, unassembled in a box at my door, a couple of years ago when I bought it (looks like you can get one for $189 now, but you probably want an upgraded model which is around $300). 

Though the out of the box Ender3 works very well, there are a few things that you start running into pretty quickly that are irksome and encourage you to make..... modifications.

For instance?

Well, the main control box sits under the build plate and it has fan right on top that tends to suck in little threads of filament that come wafting off the build. This gets all clogged up in the fan. Sure would be nice to have a forward facing vent cover. Gee.... there is one on Thingiverse? Great. Lets print that and install it. neat. 

Boy, sometimes if I leave this thing for a while the cables slouch over and get caught on the moving build plate and cause print badness. Is there some cable management system? On Thingiverse there is an entire parallel universe of 3D printer cable management systems and remixes!! Hell, some of them I designed myself!! Cable chains are a wonderful thing and lots of fun to screw with. Ok. Lets get them. 

Hey.... I want a controller for my printer. I hear Octoprint works great (it does) and it runs on a $30 Raspberry Pi. Gonna need a case for that sucker. Look <here> on Thingiverse you say? Great. (ooooh, snap together). But.... I also want a Pi Camera holder. I think I will design my own one of those (you can use it too if you like).

I don't like the bed leveling. Too hard to get things just right. Would like to try out some sort of automatic bed leveling. For that you will need solid bed holders and cable guides (i.e. get rid of the springs). Hey, I got a good design for that too. Uses some bolts for spacers. How clever!!

But, in the winter, it gets too cold in the garage to print (needs to be around 20C for things not to pull themselves apart when cooling). What to do about that? How about a thermal enclosure!! I could use some corrugated plastic sheets for walls and I could print some corner and side holders that just snap things together. Perhaps with some plastic 3D printed bolts. I made this great Enclosure (that is easy to put away in the summer). See the Pictures !! (OK, this turned out to be a big waste of time and plastic. When I make a larger one for my CR10, I am going to use cardboard boxes and duct tape). 

Stupid Enclosure

After a few years I decided I wanted to upgrade to be able to print with flexible materials. For that, you have to get rid of the standard bowden tube and get a (somewhat pricey) direct-drive attachment. I did that and things seemed to be working OK, but after a while my runs started failing because there was too much friction in the filament path. Specifically, the holder for the filament wheel was making the wheel too hard to turn and this was making the filament catch up. What to do about that. Hey, here on thingiverse is a ball bearing based holder that fits on the top of the Ender3. It works Great !! 

Snap together ball-bearing filament holder holder

And there you have it. 3 years of printer design evolution have resulted in a printer that can print ANYTHING (small) !!!  And now..... I have no idea what to do.

Bridges !! Train Lights !! 3D printed Deck !!