MakerGear Forum

I was driving home after a short trip to the hardware store, thinking people having all those problems with jams and here I am having owned 3 different 3D printers in the past 6 months and hardly ever had a jam. I must of jinked myself because I I had big jam and it took a long time to clear. I thought I found the problem, the bottom part of the extruder where it tapers down to feed into the V4 hotend had a hairline crack.

So I found the link on MakerGear Support and downloaded the V4 STL file, printed using S3D and PETG what I had in the machine. But I forgot to print Support checked so I got to do it all over again. Both being done on the suppose to be bad part. The second print came out fine, but it took an hour to get the support structure out the S3D had added and I only had the default at 40% checked.

For the life of me I could not get the new part to feed filament correctly. Seems to have a lot of clearance issues lining up with the stepper motor. I went back to the old part and bingo, it fits perfectly and no feed issues.

So is my problem the STL file I used been updated for a different style of stepper motor or is using PETG making it have the loose fit? The old one bolts right up, the new one has enough clearance it can be moved around... enough not to line up with the hot end. My machine was shipped to me in August this year I believe.

I have printed lots of extruders, for various reasons. . .

I think the answer is that it is very difficult to print a perfect circle sideways. Even with support, it's going to want to come out a little flat on the top surface. Can't be helped, although I guess you could design in a bit of a pear-shaped cross-section or something to exactly compensate for the amount of droop you get at the top of the circle. . . but that's a topic for another discussion.

Also bear in mind that the inside of any printed hole is going to be rougher than you want for guiding filament along. What that means is that generally speaking, you want to make the filament hole a little tight by design, and bore the hole out with a drill. The v4 extruder, in particular, is pretty short, so as long as you have a drill of the right diameter, you shouldn't have any trouble getting it all the way through. However, what I use is a length of electric fence wire, which is 2mm diameter. It takes a bit of force to work it through the first time, but after running it through the extruder three or four times from both sides, the bore is pretty smooth and just big enough to run the filament smoothly without catching on anything. Works like a charm. Although drilling works great, too.

[edit] Fence wire is 2mm, of course, which is good for a 1.75mm filament. Drill bit should be 2mm, too, if you use that.

Thanks Tim, I used a couple of numbered size 49 and 50 drill bits out of my one of my drill index sets and they were pretty close to the mm measurement needed. My alinement issue was with the motor. The stepper motor they are using has a certain size mounting or index ring machined on the face and my printed part was loose on that machined ring. Enough that with the play in the mounting bolts you need to have an alinement pin or rod go from top to bottom and then into the V4 Hot end. I messed with it for a time before giving up and going back to the OEM one, which took no problem to get working again. I will try to contact MakerGear Monday to get one they are currently installing on the machines coming off the line.

Well, I'm not sure what parameters you used when printing, but I've printed all of my filament drives in PETg and had no alignment problems at all. However, I didn't have any particular problem getting the support structures off, either. I even let it print a support structure inside the filament guide bore and it pulled right out. Using PETg, I've had some problems getting the motor mount to print flat without peeling part way off of the bed from shrinkage, but I haven't had that problem with the extruder. I print with a high infill (75%) to make sure the parts are solid, but everything else is more or less default. Generally, I recommend PETg over ABS for printer parts. . . it's tougher and less prone to cracks.

Well I will check with MakerGear Monday to see if they have a updated file, where did you get your file from and what was the date? Are you using the V4?

I think I used either 70 or 80% and it had no curling off the bed, I never have problems with removing either since I use PEI on the glass.

I got the v4 design off of github site. The v4 parts are in a separate place along with the dual extruder parts:

https://github.com/MakerGear/M2/tree/ma ... 4%20Hotend

The one you want is "Single Filament Drive.STL".

Well thats the one I used, pretty sure anyway. I took it into Fusion 360 and it sure looked like the one I printed but it only takes a mm or so to make it not be right. Maybe tomorrow I will take into S3D and try with less support and reprint. If your using PETG and it works for you it should work for me. Once again thanks for taking the time to reply.

I've printed a couple of those in PETG too, and it helps with that particular file to set manual supports for it, and not rely on the auto-generator. I didn't want support inside the filament hole for instance, and it's not needed on a couple of the side holes either, but you can put it in other places where you do need it.

(Just be sure to check the underside to make sure you have support put under the hidden cutout areas.)

Matter of fact, I saved the factory file for it with the manual support already in it.....just remember to change the Z-Offset to match your value. (Saves some time.)

Thanks Jules, I will get it downloaded in the morning. Normally don't change the Z offset so I guess I will learn. Maybe all the prying and cutting to get that fill out made it not fit right?

wmgeorge wrote:Thanks Jules, I will get it downloaded in the morning. Normally don't change the Z offset so I guess I will learn. Maybe all the prying and cutting to get that fill out made it not fit right?

Actually, in order to keep it from slumping/warping a bit, it needs more support than S3d normally provides. (That file i posted is a bit of a monster.)

But you should be able to pull it out with a good pair of needle nose pliers. (And eye protection, of course.)

It does take a while to get the support out, but it helps it keep it's shape better. (And if your Z-Offset is zero, just change the value that I have in there (-0.03mm) to zero.)