Cloudy acrylic engraving

[Judd Stapleton]

I have been engraving 4mm acrylic and have had a cloudy film appear around letters. I have tried wiping but it will not come off. has anyone experienced this?

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[Gene Uselman]

Are you using Air Assist- it should be very low if it is on. Also the best practice is to mask the face of the acrylic with paper tape [transfer tape]. You should not use IPA alcohol on acrylic but sometimes other solvents work [try a trial piece].

[fred ungewitter]

Another method of masking is liquid dish soap and water applied to the acrylic before lasering. I usually apply it with a brush during the lasering, although others have posted that applying it to the sheet and letting it dry also works. The latter method is probably safer overall. Once the job is done, the soap layer washes away, taking the residue with it.

[Eric Adams]

I don't believe that's residue - look at the tip of the triangle inside the "A". It has two points. Do you by chance have two pieces of artwork laying on top of each other, but one's slightly shifted left/right?

[Gene Uselman]

That shadow effect can also be the beam clipping the edge of the hole in the nozzle and reflecting some of the energy.

[Judd Stapleton]

The only thing on the bed is the one piece of acrylic.

I am going to check my beam alignment through the nozzle as it was off when I first bought the laser. It may have come loose and moved.

I will try the masking tape first and then the dish soap.

The air assist was on but the valve is almost closed so it should not be coming out very much.

Could the Max/Min power affect it. i noticed that I had not reduced the min power like I usually do when doing a fill. It was set to the same power as the Max as I had just completed a cut earlier.

Thanks Guys

[Gene Uselman]

I normally keep my min/max the same unless having problems in a curve or something- that is mainly when it comes into play on a cut- engraving you do your direction change off the material so it should have no effect.

[Judd Stapleton]

I started using the masking tape and that has cleared it all up. No more cloudy days. Thanks all for the input.
Judd