Help building a temp mod...

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sphetz
Posts: 1
Joined: Mon Oct 06, 2014 2:58 am

Help building a temp mod...

Post by sphetz » Tue Dec 23, 2014 5:21 am

I bought an up mini a few months ago and I now have 2kgs of pla and 1kg of abs from a different vendor and I cannot print it due to temperature restrictions. I would like to build a temp mod but am confused how its wired and what type to build. I already purchased this: http://www.amazon.com/JST-XH-Balance-Ex ... =jst+xh+3s . Now i just need help choosing what resistors, how to configure them, and how to wire them. I have seen rotary switches, dip switches, and push button switches and 1.8ohm resistors which i think is 5c steps and 3.7ohm which i think is 10c what should I choose? I want to be able to print my pla which the pla setting is to hot enough for and abs which the pla setting is too cold for. Also, if anyone has any info on how to wire a switch to the temp controller on the bed for a abs setting or attaching a glass bed please send it my way.

Thanks,
-sphetz

roller
Posts: 1622
Joined: Sat Oct 06, 2012 9:09 pm
Location: Brisbane, Australia

Re: Help building a temp mod...

Post by roller » Mon Dec 29, 2014 1:34 pm

I am tryng to get around to full doco on my 10 step mod so anyone can just follow the guide but the last few weeks has been cruel with respect to free time.

In the interim, you have the basics down - 3.7ohms give you 10C and 1.85ohms would give you 5C steps... this is not dead accurate for every step but a decent approximation over a full 100C drop. As I'll explain later though this accuracy doesn't matter too much.

Firstly for ABS. If you don't want to bother with a multi step mod -40C ie 14.8 ohms or there abouts is good for most aftermarket ABS. 30C will also work well giving slightly better adhesion and also slightly more difficult support removal. Either will probably serve you fine. If you want to jump into a multistep mod then for ABS 10C steps are sufficient - you will not see a noticable change in properties of your prints with 5C steps and in fact there are other factors at play which would have a greater impact on print quality than 5C steps so they are just not worth it.

For PLA generally you can get away with 10C steps but some (usually very cheap) PLA can need 5C steps to find the narrow sweet spot. As a rule this PLA will always be a pain and if you find you need this look elsewhere for supplies. Generally PLA is a massive pain anyway with a direct drive extruders (like Ups use) because the stepper motors heat softens the PLA and causes it to jam in the feed.... read through the mods on this to cool the feeder. The results here are inconsistent and your results may vary. If you want to try a fixed mod for PLA generally -20C ie 7.4ohms is what i have needed for my PLA but there is more variation with PLA from supplier to supplier.

So in the end I would still stick to 10C steps for both and be discerning about PLA purchases for a multi temp mod.

The wire you want (using your amazon image as a reference) is the yellow. Insert your extra resistors in series on the yellow and it will fool the printer into thinking it is hotter than it really is - in turn lowering the hotend temp.

If you have specific questions that you want answered faster I'll PM you my email.

On the bed mods... jump on to one of the existing threads... and see if they help ... look at maybe a PM to the users who have done one.
http://www.pp3dp.com/forum/viewtopic.ph ... 2&start=20
http://www.pp3dp.com/forum/viewtopic.ph ... 2&start=20

If you want to print ABS on glass you need at least 80C and for PLA you need 50C. I do this on my repraps but the reason I have the up is to use removable support so there is no point to glass on the Ups for me though I have used it just for kicks. On the Mini I just cut a sheet of glass to fit (borosilicate is best) where the perfboard does - this is a really handy thing about the Mini as swapping to glass required no recalibration.

roller
Posts: 1622
Joined: Sat Oct 06, 2012 9:09 pm
Location: Brisbane, Australia

Re: Help building a temp mod...

Post by roller » Fri Jan 30, 2015 12:29 am

The guide to the thumbwheel mod is now up at Thingiverse. I have added a build guide as a PDF.

http://www.thingiverse.com/thing:528396

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