Unwanted flanges on flat parts

[O'rion]

I'm printing an item in two halves I want to glue together. I'm finding that on doing the edges extend a bit beyond the nominal boundary of the object, resulting in an unwanted flange or lip that must be sanded or cut off. I've adjusted two settings without completely eliminating them: temperature (specifically, printing the first layer at a closer temp. to the rest of the print) and reducing the first layer width (now down to 70 percent). Appreciate any tips on reducing this issue.

[jimc]

The first layer will almost always be like this. This is adjusted on your printer with the z height adjustment. Generally you want the first layer gap a little tight so the plastic is slightly squished for adhesion to the bed. If you can sacrifice adhesion a bit then make your bed gap a little bigger and the flange will go away.

[O'rion]

In my case a bed calibration is performed automatically before each print (I'm using a ZYYX), so the z height adjustment is determined at print time, and not easily changed. I haven't tried a raft since I wanted flat mating surfaces and thought the raft cleanup would be more effort than trimming the flange away, but maybe that's the way to go.

[jimc]

You can still adjust the z height. If not on the machine then add the offset in s3d in the gcode tab. Add some in the z axis. Start with .05 and go from there but like i said the bigger that is the worse your bed adhesion is. What you have with that little edge is a normal part of a 3d print.

[O'rion]

Thanks, I'll give that a try.

[O'rion]

Just for followup ... Looks like this is less noticeable on some filaments. I can nearly eliminate it with Colorfabb XT just by modifying the first layer width, but hard to do so with the straight PLA I've used. Didn't notice it with ABS on the DaVInci either, but that is known to print a bit high off the bed.

[maddog7]

This was one of the first 3d printing problems I encountered.
Did you model the part yourself? If so simply add a small bevel/chamfer to the bottom of the model where the halves join. This will reduce it's footprint slightly and you won't have to compromise any of the rest of the build.
Cheers
D

[marcnicol]

Great idea!

That's straight on my list of clever little things to do

[O'rion]

If so simply add a small bevel/chamfer to the bottom of the model where the halves join. This will reduce it's footprint slightly and you won't have to compromise any of the rest of the build.

What a great suggestion! Thanks!

[maddog7]

I'm new here and pleased as punch that I might have been able to help. (I just hope it works for you)
Cheers
D