Direct Print to Acrylic - Volume

I'd process the blanks and then print. Printing and then finishing is an absolutely terrible idea.

As for the edge finish, that's a matter of opinion and customer's tolerance. Some will accept a router edge. Some will accept a sanded edge. Some only want a polished edge. If they want a polished edge, I'd call around to acrylic specialists and find out how much they would charge to put on the provided acrylic. I'd specify you do not want flame polished.

If you want to keep things in house, I'd try to go from the router right to the buffing wheel. Then clean and print.

 

It's better to print directly on flat acrylic using a flatbed printer after the parts have been routed. If you try printing direct on a large sheet and then routing afterward you run into two possible problems. First, the material registration on the routing bed compared to how it was originally set up on the flatbed printing bed has to be dead-on. Otherwise there will be alignment problems, big or small. Then the routing process may chip away parts of the print job along the edges of the material. Even the slightest bit of flaking along the edges can ruin the job. I think it's better to cut the parts first, position them precisely on the flatbed printing surface and then print direct to the material.

 

Im going to disagree with some of you guys on the router then print portion. We do a lot of this. Print 2nd surface on the acrylic first then router. Caldera has the Mirror all option now and you can print everything 2nd sided. Our inks and router do a great job on the DA acrylics. If you are using standard acrylic, there could be adhesion issues if chipping or other issues are occurring. We never go to MDF...always us a spoil blanket on our Colex machine. Make sure you have PLENTY of bits on hand.

 

We do it both ways. For an order of 200 or so I'd probably cut them first. Setting up the registration can be problematic if printing on a full sheet and then cutting because of the orientation of the "0" point. If the router and printer are the same, no problem. Chipping of the ink can occur if it's a bleed, depending on the ink set. For the ink I use, it does occur.
We are mostly a plastic fabrication shop so we cut acrylic all day every day on several routers. For a nicely finished edge I will offset the first pass .013 and then do a finish pass at actual size. We use upcut bits with 2 flutes for acrylic. Usually this will suffice, though sometimes we will polish after depending on the product.

 

He's looking at a hybrid printer there. The most efficient way is full sheets vs precut. A true flatbed, doing individual pre-cut is advantageous with the ability to pin your registration for each pre-cut pc. the FB5XX series is slow on the white ink/cmyk output.

 

I'm sorry, take no offense to this, but how do you bid or win a job and you haven't even figured out how to start the job yet?

 

Good luck with your job!

1) Do you cut blanks and then print to them versus nesting on 51x100 sheet?
For this many we would nest on a full sheet and route after. Should have plenty of room for registration marks.

2) What diameter bit do you use to cut the acrylic? Do you return for a 2nd pass to finish or just one pass?
We would generally use a 6mm bit for that type of quantity. 2nd pass isn't entirely necessary but we do it and it's a lot cleaner. Acrylic tends to have a lot of static and if the vacuum doesn't suck it up I feel like you can never get rid of it.

3) Do you used a diamond bit to polish the edges of the acrylic or use another method?

We use a diamond polishing bit. If you're printing first, and especially full bleed, which we would do, you almost have to use a diamond/polishing bit. Otherwise you can't flame polish because it will burn your ink and singe your white back. You also have to remove the masking on both sides and then you figure out how to handle that clear piece of plastic until it's up on the wall of your customer. It's also a lot of product handling and chance to scratch. Hopefully you charge for it because it does take longer and those diamond bits are expensive. Also, we just upgraded to an Automatic Router Bit Changer and it makes this step sooooo much easier. Take that into account if you have to do it manually, route , switch bits then polish, then a put another sheet on and switch back to route, then to polish etc.

4) Do you use a backer? What type? When during the process do you apply it? We used to skip the white ink and use white a vinyl backer prior to CNC'ing, but we had complaints from customers about vinly lifting on edges and pulling the ink right off with it. Do you have a better process with vinyl?

If your going to do it this way, you have to make sure you're using digital acrylic (If your printing full bleed, I would use digital acrylic regardless) or that your ink sticks really well. And this is almost a definitely route first print later because then you're dealing with ink adhesion issues, and then routing through the vinyl and that can create other issues. (Downcut bit to make sure that you don't cause it to lift)

5) How do you store the pieces after they have been printed/cut before packing/wrapping them, since they are so fragile?

We would pre cut a cardboard sheet that matches the print sheet first. (Copy the route file that is sent over and cut it out of cardboard) Then as they come off, every piece gets the exact size cover. Then stretch wrap that cover on so you can keep them safe.

6) For any newbies reading this, our first tests routing 2nd surface printed acrylic did not go so well, because we had placed the acrylic directly on the MDF spoil board of the CNC which seems to have caused a lot of scrapes and damage to the image/ink. Now we are using mats from X-edge (MatriX Mat) and that seems to have solved our "ink scrape issues".

Acrylic should have masking on both sides, only pull the one side of for printing and then route with the print side up. That way the side that is down on the router is better protected with the masking.

 

We don't use the backer, we just use white ink. If we were going to do it though, I would apply it to the whole sheet and then route. I agree that it's annoying trying to apply it after and then trim out the edges and holes.

I agree that acrylic is sharp when routed. So do you only break the edges on one side? What does breaking the edges mean? Do you use a radius bit for that? Curious because I've had this same thought of sharp edges and how to address that.

 

Possessing the quality of "charm" is one way, at least.

 

That's cool. How much do you actually bevel it?

 

Do you polish the beveled surface?
We do them like Griz.
The Zund has an auto bit changer so route with 6mm bit then diamond polishing is easy.

 

Nice. You should have no trouble then.

 

Do you guys have a flatbed application? We'd print on clear, laminate it with white...then apply it to the acyrlic. I've never liked how our FB500 printed on acyrlic... It's also pretty slow, especially when printing white. If you print on a full sheet, you will likely have some ink chipping... And if you print 1 by 1, there isnt really a way to not print on the belt -

You cant tape all 4 sides because you wont be able to push it against the alignment bar. you'll be struggling each piece trying to get the tape to go underneath. Best option if you go that route would be to female cut the shape out of alupanel or some other material as close as you can without too much struggling and use it as a jig...then itll print on the jig and not on your bet, or at least hairline on your belt.

I'm wondering if all the overspray will get on the egdes of your acrylic though - if you pre-polish it may ruin the job with overspray by printing that much bleed. It may not... we generally print on thin material so it could be ok.

I'm thinking if you have a application table, itd be faster to apply 200 pieces of vinyl than it is to print photos on acyrlic, then have a second pass printing white... The FB 550 is so slow. And it'd be more durable / look better

 

I do a lot of these. I usually pre cut and line up the sheets on a flatbed with extra space in between for edge bleeding and print multi copy. One hit one click print including white and I move to the next load. For glossy edges, I just do a little touch of torch to make it smooth and glossy before printing.