Simplify3D User Forum

Hi. I'm attempting to print a block from which a strap (approximately 1/16"x0.5"x6") protrudes from the center of one face. The strap requires support material under the 0.5" wide face above the build plate. I'm using a MakerGear M3 printer.

This printed fine in PLA, but over time occasionally the strap would break off - despite fillets where it joined the block. S3D Tech Support informed me that PLA is one of the more brittle filaments and recommended PETG as a more flexible alternative. I liked their idea because my print would be less likely to deform if subject to direct heat from the sun, etc.

After attempting to follow Jules' very helpful eSUN Black PETG recommendations on MakerGear's "Filament" sub-forum, I was able to get a very nice print... EXCEPT that the strap portion's outline shell layers delaminate completely from the its infill (almost like they were never bonded together at all), and it's next to impossible to separate the high-density support material generated below the strap.

I've experimented with many of S3D's settings (e.g. Infill Overlay, Extrusion Multiplier, Infill Extrusion Width, etc.) and I've followed recommended settings to optimize PETG bond strength (e.g. no fan, hot end = 242C), but I can't seem to get the outline shell layers of the strap to bond to each other or to the infill area. I'm also getting fine hairs, but I can live with that for now. There doesn't seem to be any delamination problem at all with the shell layers on the block, but the bonds on the strap are extremely weak and any flexing at all - including vain attempts to remove support material - causes the outer layers to separate.

Any suggestions toward achieving a strong bond in these shell layers and/or separating the support material would be greatly appreciated. Thanks! - guy

Pics would be helpful to fully understand the issue.

No fan and heat seem ok. Check speed. PETG likes slow. I generally am at 40mm/s overall.

Look closely at the preview and see if you can see an issue like gaps. Maybe need to adjust the extrusion width a bit.

Thanks for your recommendations, wirlybird. Is it safe to assume that you're recommending I try increasing extrusion width vs. decreasing it to improve inter-layer bonding (along with slowing down print speed)?

Interestingly, I ran a couple test prints in PETG of two straps of the same width and length (slightly different thicknesses) directly on my build plate (no support material required). Both prints exhibited excellent outline shell bonding - both between shell layers and between the shell and infill material.

Also, upon closer examination of a previous test print of a block with protruding strap, I realized that the generated support material wasn't spanning the entire width (falling about 1/16" short) on one edge of the strap. Neither of the shell inter-layer bonds were super strong, but the overhanging (unsupported) edge of the strap was particularly prone to delamination. I sent this information to S3D Tech Support to provide them with additional insight into my problem.

I tried to insert an image here, but I couldn't seem to make it happen.

Given this evidence I'm beginning to suspect that my bonding problem is at least partly caused by inadequate support. I've tried using high-density support, but in my (limited) experience PETG support material is very difficult to separate.

V/r, - guy

If you're not getting sufficient support along the edges of under-surfaces, try an Extra Inflation Distance of anything other than zero.

...try an Extra Inflation Distance of anything other than zero.

Thanks for the great suggestion. I took your advice and set the support material extra inflation distance to 1 mm. As expected this caused S3D to generate a 1 mm wider perimeter of support material under my protruding strap. Unfortunately this didn't seem to improve my shell delamination problem.

I looked very closely at the delaminated layers. I think that increasing my infill overlap resulted in a stronger bond between the infill and the first outline shell layer (this first shell isn't separating from the infill). Only the further-outward shell layers are delaminating. Increasing the hot end temperature from 247C to 252C had no apparent effect. Also interesting is the fact that the shell filaments bonded fine vertically to those above and below them, but these "bands" of shell material separate from each other in the horizontal plane (parallel to the build plated). There's a clue there, but I'm not quite smart enough to understand what that clue is telling me.

Maybe this isn't a support material problem, but again - when I printed a strap of equal dimensions directly on the build plate, the bonds between the infill and the outer shell layers were strong and perfect... no amount of flexing could cause the strap's shell layers to delaminiate.

Another member of this forum suggested that I adjust my extrusion width. I'll probably try this next.

Thanks very much for your advice!

V/r, - guy

I have a pretty similar Problem with my black PET Filament (ICE Filaments). Other coloured PET Filaments are not so bad but I have the same Problems there too.
Sometimes after the print you can peel of the 1st layer because the 2nd one isn't bonding to it correctly.



My Settings are:

• Extruder temperature: 220°C (Filament range 195-220°C)
• Bed temperature: 60°C
• Printing Speed: 30 mm/s
• 1st layer Speed: 33%
• Outline Speed: 50%
• Infill Speed: 75%
• Layer height: 0,15 mm
• 1st layer height: 100%
• 1st layer width: 120%
• printing on platform sticker (no Problems with adhesion of the 1st layer to the sticker!)

Do you have any suggestions what Parameter to Change to get rid of this Problem?