Small Parts and Build Speed

[ixlr8]

With 2 kids and a full time job I don't have a while lot of time to experiment so I will rely on you guys for this one.

I have been printing mostly small parts and I have been using build/tool speeds of 50/80 respectively usually.

My theory is (after 2 failed prints) is that this is too fast for a part that is maybe no more than 10mm long per slice, because the layer(s) beneath haven't cooled (hardened) enough yet to have more molten plastic extruded onto it. It seems to cause lots of warping and wet prints for small parts, but works great for larger parts that are larger than 50mm per slice because the tool spends more time finishing the slice before starting the next layer.

So what is the answer for build/tool speeds for small parts? 10/20? What would happen if I tried 10/80?

FWIW this is for ABS parts.

[Geoff]

With 2 kids and a full time job I don't have a while lot of time to experiment so I will rely on you guys for this one.

I have been printing mostly small parts and I have been using build/tool speeds of 50/80 respectively usually.

My theory is (after 2 failed prints) is that this is too fast for a part that is maybe no more than 10mm long per slice, because the layer(s) beneath haven't cooled (hardened) enough yet to have more molten plastic extruded onto it. It seems to cause lots of warping and wet prints for small parts, but works great for larger parts that are larger than 50mm per slice because the tool spends more time finishing the slice before starting the next layer.

So what is the answer for build/tool speeds for small parts? 10/20? What would happen if I tried 10/80?

FWIW this is for ABS parts.

Sometimes slower can be just as bad, too slow and the residual heat from the nozzle keeps the top layer too gooey because it's got such constant heat near it - and when they are small parts they can only be so far from the nozzle.

As you have probably figured out, the travel speed is just the speed it moves from point to point to print - having the printer printing slow and a fast travel speed causes alot of mess, spider webbing etc. if you are going super slow speed, cut the travel down to like 30ms or 40ms, if the object is only 10mm then you are not travelling very far, so no need to have it jerking around.

Watch a stepper move 10mm ... whether it does it at 100ms speed or 20ms, it makes very little difference in the print time but quality is much improved. I also would try lowering temperatures for smaller items.

If the object is only 10mm, it doesnt need to be on the hotbed too long, really its that base layer that needs to stick as its not going to be there for hours, I would be printing with no raft and no supports and at 20/40 if i got into trouble.

So far my smallest print is still a frog I did that was smaller than a 5 cent piece, or around 8mm wide, so 10mm can be done.

[JuniorJack]

Hello,

I also print small parts with ABS. My solution is to use the multiply feature and print four items the same time. It gives time for cooling, and the result is perfect.

BR

[Geoff]

Hello,

I also print small parts with ABS. My solution is to use the multiply feature and print four items the same time. It gives time for cooling, and the result is perfect.

BR

^^ this also, I remember doing this on a full size chess set where i printed a whole side out at once, the single prints would be crap but when printed together, they were great - took me a while to realise it's because they had cooled down properly.

some people use a fan to blow on the prints while printing but for me that screws everything up even more.

[Terteros]

frog_1.jpgfrog_2.jpg

Hi

I have some trouble with objects in smaller size (scale reduce with FlashPrint). First picture looks like good, but picture two shows some "errors". I don' know what the problem could be.
Any ideas?

Thomas

[Geoff]

frog_1.jpgfrog_2.jpg

Hi

I have some trouble with objects in smaller size (scale reduce with FlashPrint). First picture looks like good, but picture two shows some "errors". I don' know what the problem could be.
Any ideas?

Thomas

Ok..

Yes, your problem is easy to fix, you are not using a raft or supports.

#1 you need to use supports to print that frog. Trust me.. I have printed literally hundreds now for people.





And if you want to go super small... as in...




You print at 0.15mm layer height and about 30ms feed rate, and a lower heatbed temp, if you usually use 110c, drop it down to 106-107c, the smaller prints cant handle the heat and make edges rise easily, and thats all due to heat. The bigger the item, the hotter you go, but dont exceed 115c

[Terteros]

Hi Geoff

Yes, I didn't use raft or supports. I thought this is only necessary when I print difficult objects, like a bridge or so. I'll test it with supports (I hope I will not print hundreds of frogs... ;-) )

Thanks.

Thomas

[Geoff]

Hi Geoff

Yes, I didn't use raft or supports. I thought this is only necessary when I print difficult objects, like a bridge or so. I'll test it with supports (I hope I will not print hundreds of frogs... ;-) )

Thanks.

Thomas

It's all down to angles on the frogs chin for that one, the arms could get away with none but the chin just has too much of an angle.

If you use makerware try the preview function, it shows you all the supports and things that will be printed at runtime and you can also check out each layer of the print with a nice slider bar, so before you print you can see if there will be areas that are printed in the air, they will be a different colour in your preview.

[Terteros]

frog_with_support.jpgfrog_wo_support.jpg

Hi Geoff

Left picture (orange) is printed with support, right picture (blue) is printed without support. Left one PLA is from another than the right one. So I think this could be also the problem. Next one I'll be test with other temps. My problem is also that I'm testing with different PLA's from different
companies and every company has another coil (correct word?).

Thomas

[Geoff]

frog_with_support.jpgfrog_wo_support.jpg

Hi Geoff

Left picture (orange) is printed with support, right picture (blue) is printed without support. Left one PLA is from another than the right one. So I think this could be also the problem. Next one I'll be test with other temps. My problem is also that I'm testing with different PLA's from different
companies and every company has another coil (correct word?).

Thomas

Wow that Blue PLA looks excellent, and you said without supports?

I might go and try the Green PLA I have and see if I can do it, I'm impressed the blue layers came out so well underneath, there is no visible overhangs at all.