Poor Surface Beneath Supports

WHAT’S THE ISSUE?

After finishing a model with some support, and you remove the support structure, but they could not be moved completely. Small filament will remain on the surface of the print. If you try to polish the print and remove the remaining material, the overall effect of the model will be destroyed.

 

POSSIBLE CAUSES

∙ Supports Not Appropriate

∙ Layer Height

∙ Support Separation

∙ Rough Support Finishing

∙ 

 

TROUBLESHOOTING TIPS

Supports Not Appropriate

Support is an important part of FDM printing. But some models don’t need any support with a little adjustment. If you have to, the design of support has a great influence on the surface of the print.

 

CHECK SUPPORT PLACEMENT

Most slicing software can choose two ways to add support: “Everywhere” or “Touching the Build Plate”. For most models, “Touching the Build Plate” is sufficient. “Everywhere” will let the print full of support, which means the surface on model will be rough caused by support.

 

CHECK THE CAPABILITY OF YOUR PRINTER

Sometime the model does not need support because the printer can print a gap and relatively steep angles. Most printer can print bridging gaps of 50mm and printing angle of 50° perfectly. Create or download a text model to print to familiarize your printer with the true capability.

 

ADJUST THE SUPPORT PATTERN

Choose the different style of support to match the different type of models so that can obtain a better support-model interface. Try switching “Grid”, “Zig Zag”, “Triangle” and so on.

 

REDUCE SUPPORT DENSITY

In the slicing software, switch the view to “Preview”, you can see the supporting structure. Generally, the support density is default. You can appropriately reduce the support density and then fin-tune the printer. Try to use 5% density to see if the support surface of the model improved.

 

Layer Height

The size of the layer height determines the slope of the overhangs part that can be printed. The thinner the layer height, the greater the slope.

 

Lower Your Layer Height

Lowering the layer height can greatly improved the overhangs parts printed. If the layer height is 0.2mm, support is required for any overhang part over 45°. But if you reduce the layer height to 0.1mm, it is possible to print a 60° overhang. This can reduce the support printing and save time, while the surface of the model looks smoother.

 

Support Separation

Create a removable support structure needs to balance the strength of the support and difficulty of removal. The support surface may be horrible if you create a easily removable support.

 

Vertical Separation Layers

Some slice software like Simplify 3D can set the separation to find a better balance between different factors. Check the “Upper Vertical Separation Layers” setting, adjust the empty layer numbers, generally set 1-2 vertical separations layers.     

 

Horizontal Part Offset

The next checking is the Horizontal Offset. This setting keeps the left-right distance between the print and the support structures. So, the vertical separation layers avoid the support sticking to the print while the horizontal offset avoid the side of the support sticking to the side of the model. Generally, set the offset value of 0.20-0.4mm, but you need to adjust the value according to the actual work.

 

Rough Support Finishing

If the support structure is printed too roughly, the print quality of the support surface will also be affected.

 

REDUCE PRINT TEMPERATURE

Check the filament temperature range and adjust the nozzle temperature to the minimum for the filament. This may result in weak bond, but will also make the support easier to remove.

 

USE ABS INSTEAD OF PLA

For the models that has added support, there has a big thing with the material when doing some process such as polishing. Compare with PLA which is more brittle, ABS is easier to work. So choose ABS may be better.

 

DUAL EXTRUSION & SOLUBLE SUPPORT MATERIALS

This method is relatively more expensive. If most of your print need complex support, then dual extrusion printer is a good choice. Water-soluble support material (such as PVA) can achieve the complex support structure without ruining the print surface. 

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Post time: Jan-02-2021