Let me first say hello to this community and I’m vary happy to be here. I’m a complete noobie using a 50w OMTech machine. I hope someone can offer some advice to this problem which is not machine related but a job I’m doing and it’s related to paint on plastic.
I have side panels to cut and engrave for a case that’ll house electronics for an energy monitoring system.
I’m using High Imapact Polystyrene that is 1.8mm thick to make these side panels. There are various inputs/outputs so I need to engrave text, letters and numbers, then paint fill the text.
I’ve been using acrylic paint and engraving through masking tape but in this case, the letters are too small and after carefully weeding the masking tape off the results are just not clean and sharp enough. I can provide photos if required. Can anyone give me some ideas?
I found this with a quick search. If you’re using fill rather than line, it appears that it may not be the ideal method.
If you are satisfied with the unmasked results of your engraving, consider using a different method of masking. Apply ordinary glue stick, such as Elmer’s Washable Glue Stick. Apply as evenly as possible to ensure uniform engraving, perform the laser action and paint application. Once dry, the glue stick will wash off with water, more easily with warm water.
One could also use a similar product such as the Elmer’s glue spray, which would apply in a thinner layer but provide similar masking.
I’ve used the glue stick for unrelated but similar applications. Testing of your application is recommended before putting it in production.
Many thanks for the suggestions Fred, you could be a life saver! I’ve tried both line and fill, experimenting with different fonts. I’ve downloaded some SHX fonts.
So, would I apply the glue layer before engraving the plastic, then apply the paint, let dry then wash off the glue layer?
I’ve been researching methods, I seen one using no masking, simply covering the area with acrylic paint then using a mildly abrasive strip disk to remove the dried paint leaving the paint fill and not scratching up the plastic.
You’d certainly want to apply the glue first, as it prevents the paint from sticking, allowing it to be washed away.
Not masking acrylic is asking for trouble, in my opinion. I’d be concerned about any abrasive capable of removing paint as also being capable of scratching the acrylic.
Another benefit is that any condensed acrylic from the laser will not bond with the surface of the acrylic, avoiding the clouding effect.
Just an idea for you. I made a switch consul for my laser using 3mm white acrylic and line engraved the lettering. Then using acrylic paint simply brushed on over the lettering and immediately wiped off leave the lettering cut lined nicely filled.
Morning David, thank you for the suggestion and I’ll try that it a few minutes. The text is between 2.5 and 3.0mm high. I’ve gone with Arial GEO in Caps. Here is a photo of the job I’m trying to copy (this case was done by an experienced company)
For small text like that you might be better off not engraving it and doing a line cut slightly into the material. Meaning a vector cut at very low power. However, you would need to use a font that has a single line like CNC Vector. If you needed it thicker, then you could adjust the focus outward by a couple of mm. Just a thought.
Thanks Steve, I have actually downloaded some CNC fonts. Make it out of focus so its thicker, thats interesting. Looks great (fill) engraved through the masking, its just not professional and clean enough. I’m appreciating all the suggestions, thanks to you all.
