Posts made by Nemesis

@dc42 said in Nema17 heat, how to deal with it?:

With the belt removed, does the Y motor shaft spin freely?

Not sure what you mean exactly so I'll give multiple answers:

• The motor shaft turns freely if there is nothing connected.
• The motor shaft gives resistance when it's in IDLE 1500mA 30% idle percentage. If nothing is connected to the motor. However it's fairly easy to push through compared to any other motor of the same type.
• The belt is running on the motor shaft. I'll explain my current setup. With some images:

Since my original post I've reduced the friction on the axes quite a bit and that seems to really help in the heat department.

Also took the motors off and it seems I have a faulty motor for the Y axes. If I connect a motor clamp to it and hold the clamp with a tool I can easily make it skip on 1500mA. The motor on the X axes on the other hand is extremely difficult to make skip.

@armatus To be honest with 16mm hardened steal lead screws I would be surprised if they're bent. But I could just be too much of an optimist

A lot of force is needed to bent 16mm stainless steal rods.

@armatus Thnx for the info. Yeah that is quite a bit larger indeed!

If I'm seeing it correctly you're using trapezoidal 12mm leadscrews. I couldn't find those anywhere. Also the T10 trapezoidal leadscrews I found where quite expensive when factoring in good nuts. The SFU1205 I found was only marginally cheaper then the SFU1605. But yeah it might be overkill.

Yeah the drive couples for 12mm to 5 mm are hard to find.

The machine looks awesome! A nice clean design!

I am still planning to test the 3 SFU1605 setup just to know how well that would work.

If it's good, it's good If not I want to use v slot wheels around all vertical beams in the frame. (so 4 guidance rails)

Another thing I'm pondering is whether to use 2020 or 3030 frame components.

@mrehorstdmd From my tests yeah. It makes quite a lot of difference. Quite a bit of heat bleeds out through the heat sinks.

The motors are cold to the touch now. The motors never got hot enough to burn yourself. However the 35-40 degrees was after a 1,5 hour print. So a longer print might produce more heat. The heat accumulation is quite slow.

Edit: Been thinking about this, For the next build I'll be using Alu mounting brackets. Using the frame as a heat sink might actually work.

@vwegert said in Ideas for more realistic bed temperature control:

@dc42 Now I wish I had a FLIR to see how uniform the temperature really is on the surface and how far in I would have to go to get a realistic measurement... A shame that these things are so expensive...

I looked into buying one of those and from I have been able to deduce the precision of a FLIR is not that good. A spot measuring tool is much cheaper and far more precise. Do that's what I use now. It takes a lot more time to measure the whole bed though...

@antlestxp 1.9degree? I'll assume 0.9.

Then you have a setup similar to mine (motor and voltage wise). I'm not happy with the current XY arrangement. The frition is not to bad but still higher then I would like it to be.

Yeah agreed if I do not hold onto the printer when stopping the movement the whole printer indeed moves. But for me that is from 1100mA upward.

The XY arrangement has quite a few contact points with printed linear bearing so probably quite a bit more friction then your setup. (On a single axes I have 5 bearings) also 2 of the rods on a axes turn as well as provide linear motion.

The coolers are keeping the steppers super cool at 1500mA.

I learned a lot from the current build! Even though it has some design flaws it prints WAY better then my upgraded Anet A6.

@antlestxp 4 lead screws would be a option. However the issue with 4 points instead of 3 is that it can be a hassle to get it right and can even lead to torsion in the bed.

Also not sure if the duet wifi can do 4 point calibration.

@fcwilt It would depend on the rigidity of the bed construction. However it is something that has crossed my mind.

Thnx for the insights. I won't be able to give a definet answer if it works or not until I get all the parts and that will be a couple of weeks at least. I will post back with the results.

From my tests with the short SFU1205 I have concluded it has little to no play so it should work fine. However I am working on a lot of assumptions.

@fcwilt said in Z Bed setup with auto calibration, advise requested:

Perhaps they can be purchased but I have yet to see a lead screw that was perfectly straight.

I've ordered one and will let you know. I have a 200mm SFU1205 lying around (from china) and that thing is definitely straight. I do agree that I have never seen a straight trapezoidal leadscrew (only seen 8mm ones tbh).

As for a leadscrew not being intended for it I do definitely agree. I might add a guide to the design.

However a leadscrew is definitely not designed to be mounted on only one end and many printer design rely on that.

@antlestxp Yes they move freely. The problem with one of the axis looking like it skips steps is actually a bad motor coupling.

Do you run 1.8 degree or 0.9 degree motors. For my taste when I run a test and stop the axes by hand on 1200mA it's fairly easy to make the motor mis steps. On 1500mA it's still possible but far more difficult.

The question is what is needed though.

@phaedrux Thnx. I used these just as a test case to check the difference. Also I can put a stikker on it with Intel Inside now

After christmas I'll probably order those.

@phaedrux Will do

@phaedrux Thnx for your insights I really appreciate it and as you've surmised I'm not one to conform to standards

The SFU1605 700mm costs 30 Euro a piece, which isn't that bad! Also DuetWifi with Duex5 controlling the printer is far more expensive then the Endor3

The hair pulling isn't really an issue, I have little to non left anyway And what is a hobby project without a bit of frustration?

I'll go through the links you posted and probably fine tune the design and build it with 3 SFU1605's just to prove it can be done

Also I have a feeling that current 3D printer DYI designs are based on costs and my main goals are repeat-ability, ease of use and long time till failure.

@fcwilt said in Z Bed setup with auto calibration, advise requested:

I only have a manual leveling system. I do this once a month of so. It only takes a few minutes and the printers work just fine.

Thnx for the reply. For myself I would agree. However this machine is for my dad who has ALS. My mom isn't going to calibrate the bed for him, nor do I want her to get near the printer with anything other then a spatula to get the print off

I do not dispute the D-Bot would work great. I'm sure it does.

Would you mind giving me the reasoning behind why you would not use 16mm diameter leadscrews to do this?

@dc42 @Phaedrux as always thnx for the insights I'll keep that in mind.

Ok. I changed it to 1200mA and they get less hot but within an hour still 35 to 40 degrees. Which is still to warm for my taste.

I have now changed the Y back to 1500mA and mounted a heatsink and fan to it and have running for test purposes.

in that case a normal 4 mm drill would do. Just make sure you drill it straight! You do want to drill into your heater by accident.

@dc42 Thnx. I changed them to 1200mA they skip a bit faster now but still have quite a bit of force. Running a long term test now to see if they get hot. I am still somewhat affraid of the motor skipping steps during prints though on 1200mA. (On 1500mA there's little that'll stop them )

I also tested a run with a passive CPU heatsink and a bit of thermal paste and that makes quite a bit of difference as well.

The real culprit wasn't the heat though. My motor coupling was slipping...

@vwegert said in Ideas for more realistic bed temperature control:

Forgot to mention that the heater is a glued-on silicone mat - I'm not sure whether I could easily remove it from the aluminium plate, and I'd rather not drill into a mains-connected heater, neither on purpose nor accidentally. The end of the year is night, but these are not the kind of fireworks I'm looking for...

Ah no. Please do not drill through the heater

With a 6mm alu bed you could in theory purchase a long 4mm drill (https://uk.rs-online.com/web/p/twist-drill-bits/5226651/), drill from the side and stop in the middle. However do not attempt this without the proper tools and patience!