Idea / feature request: Minimum perimeter time

[foehnsturm 969]

The print speed even of big prints is quite often limited by the print quality of small islands (raised edges issue) as discussed here. Take the knocking over of meshmixer-generated supports as a typical example.

It's just about partially remelting tiny structures when printing 1st and 2nd perimeter and eventually infill within a second or less. Given the maximum available cooling, you have to stay below a certain print speed to get things right. But the rest of the part could be printed considerably faster.

Would it be possible to add a "minimum perimeter time" which causes the print to slow down, if a perimeter line would be finished (and the next line laid down aside) below that time?

 

[gr5 2,176]

I think before Daid would add this feature you have to convince him it is needed. You don't use the dual fans of the UM2 (or even single fan of UM1) so you might be a special case.

 

[Dim3nsioneer 557]

To be a special case is not necessarily a bad thing... :wink:

A relatively easy way to test it might be to slice it with Slic3r which allows for a different outermost perimeter speed if I remember correctly. Setting a very conservative value for the perimeter speed might be close to the effect the suggested extension might have.

Personally, I like that outermost layer speed feature of Slic3r. It gives the print a very nice and smooth look without slowing down the print too much. Maybe a minimum perimeter time would lead to a similar effect?

 

[foehnsturm 969]

I don't think that's the point here. The crossflow fan provides enough cooling to achieve the same printing speed more or less. If others e.g. can reliable print lots of long meshmixer support pillars with let's say 3 mm diameter it's indeed less important. As far as I know that's not the case. In fact, a discussion related to this issue drove my attention to it.

 

I think before Daid would add this feature you have to convince him it is needed. You don't use the dual fans of the UM2 (or even single fan of UM1) so you might be a special case.

 

[nick-foley 5]

I think the biggest contributing factor to this problem is the often-mentioned issue of Cura reversing print order each layer, so that if one layer ends on a small island, it also starts the next layer on that same small island. This can have a huge negative impact on print quality with some mode, as features get melted more than they should throughout the print.