Changing the UP Mini Nema 14 stepper to a 17

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jeeplvr
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Changing the UP Mini Nema 14 stepper to a 17

Post by jeeplvr » Tue Oct 07, 2014 2:28 am

Here is the motor I found.
http://www.ebay.com/itm/Geeetech-Steppe ... 3f3151f322
It is nearly a direct bolt in but is longer and requires a modified magnet mount. I posted the files on thingiverse for this mod. The back magnet on the mag mount is moved back 5mm to properly position the new Nema 17 motor
So far so good. It runs way cooler than the original Nema 14 motor.
The gear from the old motor fits perfectly even though the new shaft is longer and keyed. Just shove the gear on to its original position and cut off the extra shaft with a good hack saw..
Transfer the electrical plug from the old motor to the new one and you're done.

here are the thingiverse files
http://www.thingiverse.com/thing:490957

stormychel
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by stormychel » Tue Oct 07, 2014 11:42 am

Interesting... Will be my next mod, thanks for sharing!
@stormychel

roller
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by roller » Tue Oct 07, 2014 1:12 pm

Interesting.

During the length of a 2 hour print, how hot does your stepper motor get? Does it seem to miss more steps (the clicks) when doing the first layer or less would you say?

stormychel
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by stormychel » Tue Oct 07, 2014 4:38 pm

Before reversing the fan, mine got up to 80 degrees, now it usually stays below 60. If this mod keeps the stepper way below this, I'm ordering one right away.
@stormychel

jeeplvr
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by jeeplvr » Tue Oct 07, 2014 7:53 pm

Just by touch it is way cooler. My old stepper got up to 105c on some prints and so far the new stepper hasn't got over 60c. I am doing a proper comparison today when I can find my old test results with the old stepper. I will print the same model and post the results here.

jeeplvr
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by jeeplvr » Tue Oct 07, 2014 8:00 pm

stormychel wrote:Before reversing the fan, mine got up to 80 degrees, now it usually stays below 60. If this mod keeps the stepper way below this, I'm ordering one right away.
If you set up the platform clearance at .15mm nozzle clearance you shouldn't get any clicks. Also the nozzle and associated parts need to be clean. One of the things I keep forgetting to mention is the way the filament is routed to the extruder makes the stepper have to work harder to pull the filament in. Here is a picture of how I did it to minimize the stress on the extruder. It works great.
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stormychel
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by stormychel » Tue Oct 07, 2014 9:17 pm

jeeplvr wrote:
stormychel wrote:Before reversing the fan, mine got up to 80 degrees, now it usually stays below 60. If this mod keeps the stepper way below this, I'm ordering one right away.
If you set up the platform clearance at 1.5mm nozzle clearance you shouldn't get any clicks. Also the nozzle and associated parts need to be clean. One of the things I keep forgetting to mention is the way the filament is routed to the extruder makes the stepper have to work harder to pull the filament in. Here is a picture of how I did it to minimize the stress on the extruder. It works great.
Nice setup :) I was also thinking about something in that direction, came more from the idea of having my primary colors Always hanging on a bar above the printer, and just pulling the one in that I need...

1,5mm? Really? Mine is at 0.2mm...
@stormychel

jeeplvr
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by jeeplvr » Tue Oct 07, 2014 9:23 pm

stormychel wrote:
jeeplvr wrote:
stormychel wrote:Before reversing the fan, mine got up to 80 degrees, now it usually stays below 60. If this mod keeps the stepper way below this, I'm ordering one right away.
If you set up the platform clearance at 1.5mm nozzle clearance you shouldn't get any clicks. Also the nozzle and associated parts need to be clean. One of the things I keep forgetting to mention is the way the filament is routed to the extruder makes the stepper have to work harder to pull the filament in. Here is a picture of how I did it to minimize the stress on the extruder. It works great.
Nice setup :) I was also thinking about something in that direction, came more from the idea of having my primary colors Always hanging on a bar above the printer, and just pulling the one in that I need...

1,5mm? Really? Mine is at 0.2mm...
Yes, my setup works best this way to keep the adhesion of the models to the perf board. It helps to get the plastic to squeeze in to the perf holes more. Keeping the build platform level and keeping the nozzle at .15mm works good for me.
Last edited by jeeplvr on Wed Oct 08, 2014 2:08 am, edited 1 time in total.

jeeplvr
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by jeeplvr » Tue Oct 07, 2014 10:37 pm

Ok I was going to do a proper temperature survey of the stepper but after 30 minutes of printing it is barely warm to the touch. There's your research lol.
There is no question that the motor is less than 1/3 as hot as the old motor in similar circumstances.
I am using the modded mag platform I posted on thingiverse. it works really good to reposition the extruder stepper.
One thing I noticed after all this time, the back of the steppers or the covers are not magnetic. This means the rear magnet on the mag platform does nothing. I epoxied a small thin piece of metal to the back of the stepper and now the rear magnet holds everything in place nicely.
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roller
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by roller » Wed Oct 08, 2014 12:31 am

If you were printing at 1.5mm off the perfboard the filament wouldn't even stick. Surely you mean 0.15mm. I get a few clicks because I set mine low to make sure it is thoroughly pushed into the perfboard as you say.

The reason I was asking about clicks as it wouldn't indicate whether the stepper was losing steps due to being under-toqued ie the current is too low for it. Of course it is a difficult metric to assess empirically. Thinking about it, the old bucket test we used to do with reprap extruders is probably a better test ie. use the extruder to lift a bucket connected to the other end of a short (1metre) piece of filament. You keen filling the bucket (sand or water) until it starts losing steps. Easiest way to compare the torque you get with you actual setup. Of course all other parts would be equal in this design so a simply force guage on each stepper would suffice too... but I was really just curious how well the new stepper is being driven.

One other question - what is the weight difference between the two steppers. Does it make a difference to the ringing (little ripples) in the corners. Every time you do a long lay of filament in the X and turn a corner (worst case 90 degrees) you will see a little ripple formed in your print just after the corner due to the mass of the extruder "ringing" in the play of the belts etc on X. You see it on Y too of course due to the table mass. I suspect it wont have become noticeably worse but I keep my extruder mass low for this reason. Can you compare and see if there is a difference in ringing if you get a chance to satisfy my curiousity about the rigidty of the Mini's design?

jeeplvr
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by jeeplvr » Wed Oct 08, 2014 2:06 am

The calibration calls for .2mm clearance and I set up closer at .1mm or .15mm I probably wrote 1.5mm, sorry. Here is what I use to set up my nozzle clearance. The extra long feeler gauge makes it much easier to get it even across the build plate.
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jeeplvr
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by jeeplvr » Wed Oct 08, 2014 2:20 am

roller wrote:If you were printing at 1.5mm off the perfboard the filament wouldn't even stick. Surely you mean 0.15mm. I get a few clicks because I set mine low to make sure it is thoroughly pushed into the perfboard as you say.

The reason I was asking about clicks as it wouldn't indicate whether the stepper was losing steps due to being under-toqued ie the current is too low for it. Of course it is a difficult metric to assess empirically. Thinking about it, the old bucket test we used to do with reprap extruders is probably a better test ie. use the extruder to lift a bucket connected to the other end of a short (1metre) piece of filament. You keen filling the bucket (sand or water) until it starts losing steps. Easiest way to compare the torque you get with you actual setup. Of course all other parts would be equal in this design so a simply force guage on each stepper would suffice too... but I was really just curious how well the new stepper is being driven.

One other question - what is the weight difference between the two steppers. Does it make a difference to the ringing (little ripples) in the corners. Every time you do a long lay of filament in the X and turn a corner (worst case 90 degrees) you will see a little ripple formed in your print just after the corner due to the mass of the extruder "ringing" in the play of the belts etc on X. You see it on Y too of course due to the table mass. I suspect it wont have become noticeably worse but I keep my extruder mass low for this reason. Can you compare and see if there is a difference in ringing if you get a chance to satisfy my curiousity about the rigidty of the Mini's design?
I didn't weigh anything. The new motor is obviously heavier but by how much I don't know. For me the results speak for themselves. The "ring" that you speak of is most likely a natural vibration frequency of the extruder motor being excited by something, belts, other steppers etc. With the heavier stepper ( more mass) the natural frequency will be different than the motor with less mass. I could test these natural frequencies but I don't want to waste my time doing so and it isn't something most people need to worry about or can do anything about. It is way easier to print a bunch of stuff and look at the results. The motor is cool and the prints are great.

jeeplvr
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by jeeplvr » Wed Oct 08, 2014 2:27 am

Another point roller touched on is the rigidity of the design of the Mini. it isn't rigid enough by any stretch of the imagination. The table is floppy, the entire chassis is floppy but there isn't a whole lot that can be done. I make sure my machine is level ( no soft feet) and my linear bearings are new and snug. I also check my rod clips or retainers from time to time to make sure they are in place and not broken., screws are tight etc. I have the left front corner of my machine shimmed a little to keep it from wobbling.
I had an entirely new print head in my Mini and didn't notice any problems with the increase in mass.

roller
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by roller » Wed Oct 08, 2014 2:03 pm

Yeah, as an expereinced printer builder I was on top of the reasons why it exists but I was tryiing to introduce you to the term commonly used in the reprap community ie "ringing". Usually the Up linear guides and bearings are pretty good even in the Mini but there is always a little belt play moreso because they use spring pretensioners. If it did cause significant ringing it might be fixable by removing the spring and printing up a decent belt tensioner to replace it. There is some mass and print speed where these springs are going to cause a significant degradation of print quality but Ups print so slow it is probably not an issue even with your heavier stepper.

jeeplvr
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by jeeplvr » Fri Oct 10, 2014 11:52 pm

The Up's do print slow but in my limited experience if they are working correctly they print with very good detail. I have a Davinci printer that prints rubbish even on the finest settings. (rant) You look at the XYZ ads and articles for the printer and you would think it was the best thing since sliced bread. If you go to the forums and see what others really think about the Davinci and how they actually perform you see what the real issues are. I use it basically for large boxy prints that I don't care about finish or accuracy. Its a 500.00 piece of junk (rant off)
Anyway the Nema 17 stepper has changed things for the better in my case. It should be in every Mini printer from the factory. I think I paid around 18.00 to get it from China.

roller
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by roller » Sat Oct 11, 2014 2:36 am

My Repraps quality exceed the print quality of the Up especially in terms of artifacts like rigning despite having porring linear guides and heavier moving parts on the axes, but my belts are tuned properly without proper pretenionsing (not springs) which also supresses wave/whip in the belts. I have a screw based printer also, the downside is it has to print as slow as the Up but the prints are immaculate ... if only I could have removable support!

Part of the reason your NEMA17 is so cool is it will be a little under amped/torqued. Not a bad thing because it probably has as much torque on less current as the old 14 motor. Other people need to beware though not any NEMA17 may provide such good results. The one you posted has a quite a low current rating so it's getting a decent current from the Up in relation to it's intended operating current. I think I I put one of my high torque motors on there it would lose steps.

jeeplvr
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by jeeplvr » Sun Oct 12, 2014 2:59 am

The motor I chose is working wonderful. With the stl file I made for the mag mount it is a no brainer. Wire colors match exactly and so does the gear. I am super happy with it.

pleppik
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by pleppik » Sun Oct 12, 2014 4:10 pm

roller wrote: Part of the reason your NEMA17 is so cool is it will be a little under amped/torqued. Not a bad thing because it probably has as much torque on less current as the old 14 motor. Other people need to beware though not any NEMA17 may provide such good results. The one you posted has a quite a low current rating so it's getting a decent current from the Up in relation to it's intended operating current. I think I I put one of my high torque motors on there it would lose steps.
Roller: I'm contemplating a similar mod to my old Up Plus. Do you have any suggestions for a resource for stepper motor specs? I.e. other than the physical specs, what should I pay attention to if I want to be confident to get a stepper which will plug into the Up and work without blowing something up?

roller
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Re: Changing the UP Mini Nema 14 stepper to a 17

Post by roller » Mon Oct 13, 2014 7:57 am

What you really want is the current specs to be very close to the NEMA14 you are replacing and the torque to be greater. The max output current from the printer will be essentially the fixed point we need to work around. The more under current you run your new stepper the more torque you lose (but also the cooler it will generally run). If you narrow it down to a shortlist chose the one with the lowest voltage in the rating.

So I guess the search starts with trying to get the specs for existing motor. I have a feeling they might have been discussed before on this forum ... google may help you find it.

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