Joe7Batt
Posts: 3
Joined: Thu Jan 26, 2017 4:27 am

First few layers after raft shrink in

Wed Feb 08, 2017 7:50 am

As the title says I am having a problem with the first few layers after the raft.

When printing a test cube of ABS the first layers after the raft seem to shrink in at the corners slightly. After the first few layers ( say 2mm at 0.3mm layer height) it returns to a nice even normal print.

I am using a Flashforge Creator pro and the bed is heated for the ABS to 110 with the extruder at 230 and multiplier at 1.01.

I have looked for solutions and cant find any so please forgive me if its been covered previously.

bludin
Posts: 11
Joined: Wed Mar 23, 2016 10:18 am

Re: First few layers after raft shrink in

Mon Feb 13, 2017 2:05 am

I can offer an explanation for the first layer only: In order to reduce the adhesion to the top raft layer, the first layer is extrude from a certain height (the separation distance). This also results in the thread being pulled a bit to the inside of a curve/corner.
This effect can be minimized by printing the first layer more slowly (and by decreasing the separation distance). You might also try playing with the extrusion temperature a bit.

Xray965
Posts: 7
Joined: Sat May 27, 2017 11:15 pm

Re: First few layers after raft shrink in

Sat Sep 30, 2017 4:36 pm

Having the exact same problem here if I got down to the limits of the raft adhesion level between the raft and part it will bind and or not bind, there is a compromise as mentioned earlier, you will notice that the first 3 layers shrink relative to the raft adhesion limit, increasing or decreasing this will vary proportionally.

- Option one play with fan or extruder temp see what it shows.
- Option two Support should consider adding a layer scaling for the first layer of the part to the raft and that would resolve the issue.
- Option three build your part in whichever CAD software your using and compensate this pay attention when your dropping the parts to the table thou.

Ideally Simplify3d needs to consider this feature for future updates. Something similar to the scaling function but layer wise. :idea:

Note after posting this : You can change the % of the first layer after the raft by setting the difference in First Layer Width will give it a try in a few and see the results.

Xray965
Posts: 7
Joined: Sat May 27, 2017 11:15 pm

Re: First few layers after raft shrink in

Sat Sep 30, 2017 7:22 pm

After testing there is more settings to work with using raft and trial and error, whereas if your objective is to hold down the part to the heat bed for preventing part lift off especially with ABS, and not using any glue to the bed, then I would suggest using the skirt brim and offset it to the tolerance of your print machine.

Less headache less work and part holds its dimensional accuracy. :D

4dds
Posts: 1
Joined: Tue Feb 06, 2018 2:24 pm

Re: First few layers after raft shrink in

Sun Feb 11, 2018 11:08 am

Hi S3D Team!
Is it possible to get more options for first layer after raft in the future updates.
Nice to get outline speed, solid infill speed, solid infill width.
The new options in 4.0 - Additions-Above Raft Speed is nice, but not always helpfull.
I try to print materials like PEI (Ultem).

Thanks!
Best Regards!

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