View Full Version : Photopolymer?

Scott Shepherd
10-20-2007, 11:01 AM
Been asked to quote a job that specifies "photopolymer".

I'd love to quote it, if I only knew what it was. Any ideas?

Mike Null
10-20-2007, 12:01 PM
Here's from Google.

Photopolymers are imaging compositions based on polymers/oligomers/monomers which can be selectively polymerized and/or crosslinked upon imagewise exposure by light radiation such as ultra-violet light. For final use, they are made into different forms including film/sheet, liquid, solution etc. which find outlets in printing plates, photoresists, stereolithography and imaging. A popular use of liquid photopolymers is in making of rubber stamps. Photoresists are used to make integrated circuits, flat panel displays, printed circuits, chemically milled parts, MEMS (microelectromechanical systems) etc. Similar liquid compositions can also be used for non-imaging applications such as adhesives, coatings and inks. A photopolymer product can be applied as a very thin coating as in liquid photoresists or formed into a large model as in a stereolithographic equipment.

A common use is in screen printing and sandcarving.

Scott Shepherd
10-20-2007, 1:45 PM
Thanks Mike, I read that already and still didn't understand it. I was hoping someone here would be familiar with it and say "Oh, that's just another name for blah blah blah" and tell me where to get the equipment to do it :)

I've spent a lot of time looking over their drawings and they all call for photopolymer of outer layers to match pantone colors given.

Scott Shepherd
10-26-2007, 8:28 PM
Been working on the "photopolymer process" thing for a few days on and off now. Google hasn't been too helpful, but I recalled stopping at a booth at a trade show and hearing them mention it. So I pulled out their brochure, sure enough, they did it. Picked up the phone, said "what it is and how does it work?" and got a little bit of an explanation.

It's a masking process similar to silk screening. The put some sort of resist (I'm guessing) on using a screening process. Then it heads to a bath that eats away at the surface, leaving all the material with resist higher. So it's a way to get ADA compliant surfaces etched from the top surface down instead of cutting out profiles and building them up to the top layer.

Once it's out of that process, they paint the surfaces.

He said it's the lower end process for signs that they sell, so apparently it's cheap to do.

Richard Rumancik
11-10-2007, 10:22 AM
Hi Scott

I realize this info is probably too late to be useful this time but for future reference check out this site:


They have some good info as well as a video. It is a large download but is interesting to watch.

The salesperson you talked to did not give you the best information. There is nothing that "eats" the photopolymer; in fact it is the reverse. The photopolymer cures (solidifies) under UV light. So you make a negative of the image you want and place it on uncured photopolymer sheet. The UV light shines through the openings in the negative and cures the resin. The uncured resin is washed away.

You need a bit of equipment for this process. I suppose some of it could be home-made if you wanted to experiment. Novapolymers sells a combo machine which does several operations. You could do the exposure in one workstation, washout in a second, drying in a third, etc. Some of the equipment may be common to other processes (like sandblasting, photoetching, screenprinting, stampmaking, etc).

Rubber stamps can be made using a similar process but I think they often use liquid photopolymers. The sign polymers are much harder materials.

Scott Shepherd
11-10-2007, 1:39 PM
Thanks Richard, that's very helpful. They also have a booth at the upcoming Sign convention in Atlantic City at the end of the month. I'll check them out while I'm there.

Thanks for the link, it was very informative and helpful.

Scott Shepherd
11-20-2007, 8:13 PM
Just to update in case anyone wants to know. I've been researching this process and here's what I know so far, in very simple terms (since I can't speak with any real knowledge of it at this point).

There is a material that consists of a substrate (can be clear or not) and on top of that, bonded with a special adhesive, is another 1/32" layer of a plastic that's called a Photopolymer. Appears to look like just plastic. I believe the substrate is a PTFE type material if I heard correctly.

So you have the material that's essentially a two ply material. You take your image from Photoshop, Corel, or whatever else and you create a negative in a special machine or printer. They make a low end printer that will print the negative. They also make a negative machine that will product negatives at a much faster rate. Price difference is $500 for the printer, $5000 or so for the negative machine.

So you have the negative made, you place it on the material blank and put it inside the processing machine. It exposes the product to UV light. The UV light goes through the negative and exposes the material under it, which hardens solid. The rest of the material is not hardened. Once it's exposed properly, you remove it, place it in the top of the machine, face down, which exposes the face to a brush assembly which scrubs off all the non-exposed material, leaving nothing but the surfaces that were cured through the negative being exposed to the UV light.

The brushes scrub away every last bit of the photopolymer material, leaving nothing but the substrate and the cured areas (text, braille, raised features).

Once that's done, you need to cut it to shape via a shear, laser, or router (or anything else you want to cut it with). From there, it's ready for paint. You have to paint the sign. You can use clear material so all the artwork (printed, vinyl, or painted) can be on the backside, or you can use non-clear materials and paint the front side of things. To get paint on the raised features, it's commonly silk screened with an open screen (no image on the screen) or can be hot foil pressed.

Cycle time from start to finish is 25 minutes, but once you take the first part out and move it to the next station, you can load the 1st station again, so it means a cycle time of about 5 minutes. Every 5 minutes you'll have a finished blank coming out of the machine, which can consist of 1/2 dozen or so signs. So you can do an ADA sign in about 1 minute or less, then the time it takes to paint.

Cost to get into it appears to be in the $25,000-30,000 range to get all setup for production.

Interesting process. Hope that helps someone in the future who might be looking at it. If I learn more, I'll post more. I plan to speak with them late next week at a trade show, so I'll report back then.

Richard Rumancik
11-21-2007, 6:56 PM
Thanks for posting this Scott. I am sure it will be helpful.

The $25K price tag seems steep to me - take a good look at the machine when you are at the show. I am not against anyone making a dollar, but it really isn't that high-tech. If anyone wants to get into this business, you need exposure, drying, and washout stations. You will need something to make a quality negative. If I were getting into it, I would do it the cheapest way until I found that I had a market. eg build a small exposure unit (or buy one); use a fan heater for drying, and maybe a parts washer and brush for washout (could be motorized). This equipment will take a bit of room but it is inexpensive.

At the beginning you might even be able to send your files to a service bureau for negatives if you are close to a city. (Or find someone in a different business that has a negative/film printer - like a pad printing shop).

At least, that is they way I would do it before I put out $25K for the integrated unit.

Scott Shepherd
11-21-2007, 8:18 PM
Richard, that was the steep end with all the optional higher end equipment.

The machine itself is about $11K, then the cheap printer is $500, then the shear they offered was about several K, and the higher end, high capacity film processor was like $6K. On the low end, you could get by with maybe $12-13K, but if you plan to do it right, I do think it's more in the mid 20's to get all set up.

leon buber
12-09-2007, 2:23 AM
hi Richard

photopolymer process is not that expencive and you can also produce a simple UV machine by your self.
for more details you can also try m&r marking - they sell rubber stamps materials and this is one of the most common usage for photopolymer.
if you want to build the UV machine by your self (i estimat cost of no more than 500$) please feal free to contact me.

Bill Cunningham
12-09-2007, 1:39 PM
Son-of-a-gun... I've been using this stuff for years, mostly for making hot stamping dies.. Didn't know they used it for signs.. There are a few types of polymer sheets, the ones I generally used, are washed out with water after the initial exposure. They have a metal back, and the washout has a rotating plate with a magnetic coating that holds the polymer sheet. in the box is warm water, and a big brush.. The polymer rotates in a fig. 8 motion and eventually washes out all the unexposed polymer. it then goes into a oven dryer that keeps air flowing across it at 40deg C. Once fully dry, it goes back under the lights for a post exposure.. It can then be used as a printing plate, or hot stamping die.. This polymer however is not water resistant, and exposure to water will ruin it.. I would assume the polymer for signs might be a outdoor type, that would require special solvents to wash out the exposed sheet.. This would make that machine much more expensive, and less eco friendly to get rid of the solvents when expired..

Scott Shepherd
12-10-2007, 8:50 AM
Hi Bill, no special solvents needed, just water on the unit we looked at. We asked for some pricing examples and were told that the method for figuring retail pricing was about $1 per square foot. That's $80 for an 8" x 10" sign, which is pretty steep. Good thing is that once it's making signs, it'll crank out a 18" x 24" sheet full of signs in about 5 minutes. So you could get 4 signs every 5 minutes on a full sheet. So just over 1 minute each for the blank, ADA compliant. Hard to compete with ADA signs on the laser with that. I can't gather up all my braille balls and glue in 1 minute, and here, the sign is completed.

Of course that's the easy part. Painting them is the challenge. It requires a polyurethane paint. That's where the cost does enter the blank. They do have a lot of blanks that don't require painting though.

Scott Shepherd
01-01-2008, 10:17 AM
It was brought to my attention that I had entered some incorrect information in that last thread. It's $1 per square inch, not square foot. My fingers must have been moving faster than my brain that day :) If it was $1 per square foot, we'd all be going broke!

Bill Cunningham
01-29-2008, 8:44 PM
I was thinking "my god!!!" thats cheap.. What have I been using all these years.. Yup, 1$ sq inch is more like it.