dennisjm
Posts: 342
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perimeter speed not honored uniformly

Sat Jun 14, 2014 8:29 am

Attached factory file. You can see in the gcode preview the speed is not being adjusted down until the top of the part. It's printing the shells of the part the same speed as the infill up until the last 1/3 of the part but the shell is supposed to be slower the whole part I'd think.

This causes my gear teeth to not be as nice as I'd like on the actual print.
Attachments
knifegear.factory
(27.22 KiB) Downloaded 128 times

AndersE
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Re: perimeter speed not honored uniformly

Sat Jun 14, 2014 9:31 am

Does in not help if you set speedoverrides to more than 15 sec? For example 25-30 sec..

dennisjm
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Re: perimeter speed not honored uniformly

Sat Jun 14, 2014 10:08 am

AndersE wrote:Does in not help if you set speedoverrides to more than 15 sec? For example 25-30 sec..
Perhaps helps a little. Not really though. If you look at the first layer above the raft it's actually printing a lot faster than it's supposed to. In fact so fast when I printed the part those couple layers had bad adhesion and came off the part. The top that prints slow like it's supposed to worked out really nice.

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jimc
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Re: perimeter speed not honored uniformly

Sun Jun 15, 2014 9:23 pm

i loaded up your factory file and sliced it. i dont see a problem. its exactly as i would expect. the upper 1/3 is blue and slow because the time per layer is kicking in. your perimeters are printing slower than infill as you can see. something like this should really be printed with other items to control the heat so each layer has cooling time.
Attachments
Screen Shot 2014-06-15 at 9.21.08 PM.png

dennisjm
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Re: perimeter speed not honored uniformly

Mon Jun 16, 2014 10:28 am

I think you're right and perhaps I just expected the outline to always be blue since the top was blue. So I could for this particular model probably just lower the outliine speed more to get what I want.

There are still some anomalies though.

Consider the first layer
Screen Shot 2014-06-16 at 8.20.21 AM.png
Why is it printing really fast compared to the 2nd?

It does the same thing again when the support layers stop after printing the layer below it really slow again.
Screen Shot 2014-06-16 at 8.25.18 AM.png

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jimc
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Re: perimeter speed not honored uniformly

Mon Jun 16, 2014 8:48 pm

its an interface layer. its printed really fast over top of the raft to keep bonding minimal so the raft can be removed easier. same thing with the one layer thats over top of your support. it boosts up speed to keep it from adhering to the supports and also to bridge to gaps.

dennisjm
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Re: perimeter speed not honored uniformly

Mon Jun 16, 2014 9:22 pm

That would make sense on the bottom layer although I haven't seen this on other parts. I usually don't print with a raft but this part needs it because I can't get support structures to stick to the bed very well. Usually 90% of them stick and one comes off and messes up the print.

Beside the point though... the middle layer going fast doesn't seem like a good idea. That's a solid part there.. it isn't supposed to be coming off! :)

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jimc
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Re: perimeter speed not honored uniformly

Mon Jun 16, 2014 9:46 pm

well speed doesnt make an extrusion weak or not bond by itself. usually over top of support the very next layer, if infill, will print quick and what seems to be a slight under extrusion. basically its bridging. it really does work well for that. the one thing i hear from many people who have used other slicers is that the s3d support removes very easily.

dennisjm
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Re: perimeter speed not honored uniformly

Mon Jun 16, 2014 9:56 pm

True true, I wasn't referring to the part over the supports. They work fine. I was referring to the one layer of solid part before the gear part starts. It seems to have worked fine but seems weird that that one specific layer printed faster than the others. Not that big a deal probably.

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