questions about cutting plastics- laser? routing?

[motman241]

Some questions about laser cutting plastics. I have a project I would like to see, so I'm looking for some help. The places I've seen so far only offer 90-ish degree cuts (I guess it's close to 90, but might be a tad off). Can you do laser cutting at angles? Say for example I want a square cut out, but at 45 degree angles. So it's sort of a trapazoid shape. Yes?

About plastic, then.... I'd like a colored plastic, but then have a different color on the top of it. Like most name plaques and stuff, you know - black plastic with a gold top, so when it's etched, it looks like black on gold (or gold on black). Is this a custom thing? They aren't painted or leafed liked that are they?

*edited to add a picture. This is a rough quick idea of what I'm looking for. If someone can do like this picture, they can do exactly what I'm looking for. Anyone?

 

[Rebelscum]

Re: questions about laser cutting plastics

Some questions about laser cutting plastics. I have a project I would like to see, so I'm looking for some help. The places I've seen so far only offer 90-ish degree cuts (I guess it's close to 90, but might be a tad off). Can you do laser cutting at angles? Say for example I want a square cut out, but at 45 degree angles. So it's sort of a trapazoid shape. Yes?

About plastic, then.... I'd like a colored plastic, but then have a different color on the top of it. Like most name plaques and stuff, you know - black plastic with a gold top, so when it's etched, it looks like black on gold (or gold on black). Is this a custom thing? They aren't painted or leafed liked that are they?

*edited to add a picture. This is a rough quick idea of what I'm looking for. If someone can do like this picture, they can do exactly what I'm looking for. Anyone?

No, can't do it like that with a regular flat bed laser. You could do it with a cnc though by loading up a 45 degree cutter.

There are materials out there that are laminated so you cut through one material to reveal another though.

 

[motman241]

Re: questions about laser cutting plastics

No, can't do it like that with a regular flat bed laser. You could do it with a cnc though by loading up a 45 degree cutter.

Good to know. Thanks. Do you think a router might be the way to go? I've always had terrible luck routing plastics before.

 

[Too_Many_Cars]

You can get that sort of effect with a laser table and a lot of practice de-focusing the laser so you get a wide cut on top and a small cut on the bottom (I've gotten a 30 degree angle which needed a little cleaning up with sand paper on a 1/2" piece of acrylic), but it's quite difficult to get consistent results. If you're working with a forgiving material like ABS or delrin I would buy a chunk at your local plastics shop and give it a go with a router and some very careful clamp jigs... if you need something brittle like clear acrylic I'd definitely go with a CNC shop and pay the higher price for a more controlled part.

What size/thickness/material do you need?

--Brian

 

[motman241]

I'm looking to make a custom guitar amp logo. Solid, colored plastic.... maybe 1/8 to 1/4 thick. I'm flexable on thickness as long as the process and colors are correct. Right now, it looks like the process is more of a problem than I first thought.

 

[motman241]

Any other suggestions or options? Nobody here does this kind of work?

 

[Westies14]

You could certainly use a CNC router with an bit that will create that bevel - but if you want to do it with a laser I think I have an idea that might work:

Cut two pieces. one very thin bottom layer, which is the outline of your wider/base shape. Then cut a thicker layer, which is the top outline. Epoxy them together, then fill the corner all the way around with bondo and wipe it away with your finger. Once it's cured, sand it smooth! It's a bit of work, but would effectively create your bevel.

Good luck with your project!

- Douglas

 

[motman241]

Don't CNC routers typically work with metal? Are there any shops the will do plastic? Anyone on here?

 

[tim]

^ Good point. I wonder if there would be concerns with melting or fracturing of the plastic if a mill intendeed for metal were used.

 

[motman241]

No CNC routers here?

 

[CustomCreations]

Well, to get the 45deg. angle spot on Id use really good double sided tape and tape the acrylic sheet to a bed of MDF if you can. You can keep any protective covering on too. That way you can rout through both materials at the same time, ( but not all through the mdf!) which takes the cutting stress off the acrylic, and also holds it to the bed to stop it flipping out etc. Use meths or lighter fluid to seperate them after cutting.
As for colours, you could bond two colours together quite well if its a small sized job. However, you could always spray a colour to the top face prior to cutting, which might work for you, just remember to lightly sand the face prior to spraying to stop the paint lifting or chipping later.
You can buy double colours sheets especially for engraving, but they are normally quite small sizes.

You do get a very slight angle to lazer cuttings actually, to allow the piece to drop out. prob around 1 or 2 deg though!!

 

[cboath]

You could rapid protype it, then either cast or paint it.

 

[Rebelscum]

You could certainly use a CNC router with an bit that will create that bevel - but if you want to do it with a laser I think I have an idea that might work:

Cut two pieces. one very thin bottom layer, which is the outline of your wider/base shape. Then cut a thicker layer, which is the top outline. Epoxy them together, then fill the corner all the way around with bondo and wipe it away with your finger. Once it's cured, sand it smooth! It's a bit of work, but would effectively create your bevel.

Good luck with your project!

- Douglas

this idea would work great with two pieces lasered.

if you use a cnc which will cut wood and acrylic fine as it's just a computer guided router, you can't get inside square corners since the cutter is round. using the laser with an offset would set you up for some good bondo work.

 

[exoray]

I would get some brass surfaced engraved sign sheets... You know the stuff they make desk name plaques out of like this link...

http://www.myengravedsign.com/MES/Custom-Brass-Signs.aspx

From that someone with a real cnc router can cut your shape out... Most of the sign shops that do these signs use very limited and fixed machines or have limited knowledge of how to do anything beyond the standard fonts and styles... With a full featured cnc router and this material it should be pretty straight forward for anyone with the knowledge and tool...

I would offer to help but my cnc router is still in the box, I have not had enough time to set it up and don't know when I will...