Hello, I am trying to print a small rectangular window with a perspex window in it. Currently we print the frame with a cutout and then glue the window in from the back and it butts up against a 1mm ridge in the top of the frame. Occasionally the windows fall out and what we are thinking of doing is to print most of the frame up to the top of where the window is, put the window in and then print the rest of the frame. Is there a way of stopping the nozzle travelling over the window and possibly damaging it?
Cheers
Mike
Well… since you only provided a sparse description(pictures would have helped), here’s sparse answer; try to redefine the build plate area. 
If I have well understood. You are printing the frame, face sitting down the bed, pausing the print at a certain height, inserting an acrylic panel and resuming the print?
And you want to prevent the nozzle from scratching the acrylic panel?
Maybe try to enable or increase z-hop
Maybe I didnt understand correctly, but after putting the window, you will print the rest of the frame on the window surface, correct? The nozzle will not drag in the window if you have set up everything correctly correctly. You must print the “rest of the frame” on a planar surface, which entails the window, so the first part must have the exact depth (“cutout”) to fit the window.
What I have doubts about is the filament bounding against perspex.
Edit: The window shouldn’t fall within the current concept, even if it is exposed to sunlight. Either the tolerances are too loose, or the adhesives aren’t adequate.
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Hi and thanks for the thoughts and ideas. I eventually made a modified filament where I increased the Z hop at the point where I paused the print to insert the window. A test run proved this to be the answer.
Thanks
Mike
I called it EMBEDDED printing and started a topic in a forum about this a few years back.
I needed a way to get electronics and a tiny battery inside a printed fishing lure…
Let me try to give you a quick run down:
Create two models.
One for the bottom part of the frame, the other for the top to be added after the window is placed in.
Assuming your printer is well calibrated and the window is 30x40mm with a thickness of 2mm…
Have the cut out for the window in the bottom model at 30.025 x 40.025mm.
The ridge around the window should be the same 2mm.
Print and place the window inside - you can take the print out as it is just a test.
Using the shaft of your calipers check if the widows is a true and flat fit!
In almost all cases you will find the window slightly protruding out.
As you can’t smooth things mid print by sanding you need to factor this difference in!
Let’s say that in the worst spot the window sticks out by 0.08mm.
This would result in the nozzle bumping into it …
Make the cut out deeper or increase the ridge around the window to match so you have a GAP of no more than 0.15mm to a max of 0.18mm.
Adjust the top model accordingly and use the same or any matching overlap for the window and used on the bottom part.
Depending on the slicer you either import both models and add a pause between them or note the actual height of the bottom model you figured out to add a pause at this layer for printing it as a single model.
I prefer the first option for several reasons.
It can take a moment to put what you need into the model and to ensure the print can continue as planned.
During this time the model cools down and when the print resumes you can struggle with the layer adhesion.
You can use a hair dryer or small heat gun to re-heat the top of print before resuming but that’s a hit and miss as you never know the actual temp.
But using two models you can print the bottom one without top layers and the top one without solid bottom layers, giving the impression of one complete print.
Pay attention the preview though as some infill types and result is a mismatch!
And of course: If the model requires supports make sure the automatic ones won’t try to place them where the window is 