foil temp settings
We have an original Heidleberg Goldboss foil unit ( Watlow controller ) control unit. We are set at 250 and can get a good useable image. If anyone else has one of these I would like to know what you run at for speed and controller settings. We wanted to fine tune our heat and got a laser temp reader. We know the laser reads correctly. The laser says the plate is only at 160-170f. Our Infinity foil is designed to run at 240F. If I up the plate temp to run that high the foil wont adhere it randomly sticks. We are running at 2000 - 2500 on the Windmill. At that speed we know our dwell time is a little longer and we are ok with that. We are wondering if the high temp at slow speed was causing the issue with the foil. At the slower speed and lower temp we get a good tear away and all looks good. What bugs the crap out of me is even though it works according to the info I have this should not be working. Is the lower temp and slower speed ( longer dwell time ) a good thing and does this help explain why this is working. We hate when we cant figure why something is working when it should not be.
Those laser temp. readers don’t really work on reflective surfaces as far as I know, so you won’t be getting a true reading if you are reading over aluminum, magnesium or other reflective metal.
Stick some pieces of masking tape next to the die and read over that, you’ll probably get the much higher reading that is actually on the surface of the die.
This is from my experience, hope it helps.
enriquevw, thanks for the idea. I never thought about the laser bounce off reflective material. I am going to take a piece of teflon tape from my shrink wrapper and see what it does. What temp do you run foil at
You’ll want to use something black in color to get the most accurate readings. You could spray paint an old engraving with a heat-resistant black paint.
If the reading at the surface differs from your temp setting, there may be a way of calibrating the unit to actual surface temps to be most accurate. The sensor may be mounted in the block, which does not necessarily give the same reading as at the exposed surface of the die. If not adjustable, just make a note of the best setting for the materials upon which you are stamping, and keep a notebook of results.
John Henry
Cedar Creek Press
JHenry- Thanks for the input. We are new to foil. We put in a new thermocouple and heat rods and completely rebuilt our plate. At some point we want to get a new controller but for now we are using the original unit. We are not sure if the controller is reacting correctly with the thermocouple and giving the true temp. Part of the issue is getting a true temp read off the plate. I think if I can get a good temp read from the plate then I can set the controller to yield the proper output. I feel like I have a car speedometer that says I am going 120mph but a radar gun that says I am 70mph and I am not sure which one to believe.
I’d be more inclined to think that if you are getting a good release your temp. is about right. (240 range)
The 170 range is just way too low, you’d need to stamp and dwell for a couple of seconds maybe 5 seconds to get a release at that temperature.
I think the laser gun is off.
watch for pre-heating foil. if it is, near the “next image” on the foil, you may have draw that part through to fresh foil. This also brings out, that if the foil is too close to the die plate, it will pre heat. this often works as a huge hindrance to a project.
Depending on the image, 2000-2500 can be very fast.
Dont worry about it working. just be glad it is. You will have plenty of opportunities to pound your head when it isn’t.
Hi Ericm, Thanks for the feedback about preheating foil. We had wondered about the issue of preheating and always run three sheets tossing the first two. We have started having our foil rolls rerolled to both move it away from the die and get a better roll tension. The foil no longer drags on the chase and it is much easier to control the roll feed. Over the weekend we did a test of raising our heat to point where the foil adhesive kind of actually stuck but separated from the foil (ie no foil stuck to the paper) and a very low temp where nothing would stick. We also played with pressure to find the happy point where it worked like should. We have continued to test and did get useable results for both pigment and standard foils. The only foil we had issue with was the holographic foil. It looked OK but the tear away kind of sucked.
Also, I am going to see if I can adjust the motor to allow me to get the speed even slower, good idea by the way. Right now 2100rph is the slowest I can get it to go and that was after I adjusted to motor and belt. I guess it is time to get dirty, get the tools and get the beer.
I took heat reading today with the laser gun for just about any object I could get it to read. I had not tried that before. Since the cold base and everthing I tried all read at around room temp we now believe the gun is correct.
Foils are not meant to be interchangable. just because a basic Gold works, is no guarantee that a pigment will. same for holographic. Each of these is it’s own “animal”. Pigments all use a wide variety of of chemicals and no two are the same. There can be a wide variance among a manufacture’s different batches or lots of the same color.
Holographic foils are embossed into the metallic layer of the foil before adhesive layer is applied,and can cause a tough release after.
ericm - By the way my slowest speed is 2400 - 2500 on the windmill. Since moving the motor any more would only get to 2200 min speed hardly worth it. Thanks for the feed back, we do listen and learn from what you tell us. We are going to footprint the controller against the heat gun. We figured if we can get a reading on the laser and up the pid on the controller and get a new reading we should be able to get a handle on where our temp is at, what works and what wont. This was the first time I had worked with copper dies and they did seam to balance better. It was nice get a true square cut on the die and made a whole lot easier to lockup. Plus they CNC cut them with a bevel.
Ask your foil manufacturer, if you can’t find him, them come back to me for a name.
ya, Windmills “can” foil stamp. there is no doubt about that. But, often they may not be the best choice machine. A) won’t run slow enough; B) does not hold much foil on press. IE constant reloading of small length foil rolls. C) no air blast separation; D) difficult or no available gripper bars in shop. E) no clearance on plate for thicker impact layer if needed
ericm- thanks again for the info. We are going to see if we can get the speed any lower. We played with the heat and pressure and get a decent looking product. We still have issues with small text wanting to plug all little and a somewhat rough tear away. We starting with a temp to low to get the foil to stick and worked our way to a point of good contact. We are working with Colorplan and wonder if softer cotton styled grades are part of the issue with foil. The Colorplan took a nice hit for inked letterpress. We get good results on Classic Crest with foil and wonder if the more calandered sheets make it easier for the foil to stick and pull away. I could see where a softer cotton sheet ( like Lettra) would take more pressure to press the stock to a point where the foil sticks. Your speed comment has us wondering also what stocks we can do the best job with based on our equipment.
The slowest my windmills go is 1500. I use this speed for washing up. Any faster you might make a mess. I run them no faster than 2500. I think you just have to adjust the motor and belt.
Dennis - the slowest I see on the pully is 2200. It is good to know I might be able to slow it down that much
I timed my press (10x15) and it timed out at 1620. The manual states the slowest speed for a T model is 2200 and a GT model can go 1600. I’m not sure why, but maybe I have a longer shaft on my motor so the belt can bottom out or maybe it’s the way the motor is situated. I’m sure someone out there has the answer.
I run my redball from 1750-2700 and blackball 2000-3500 I’m sure I could go slower with a slower motor or ac invertor but at some point there would be insufficient air to operate the feed system
Hi Mike, Thanks for the feedback. We actually worked on the pulley hoping to slow it down. We oiled and cleaned 50 years of crap out around the spring with a toothbrush, my wife didn’t notice the gray crest toothpaste color on her toothbrush. It looked showroom new, I was so proud of myself. I started it up and it ran same speed but looked dam good doing so. We are getting a rubbing or belt scream noise when we try to drop below 2500. I think motor is a little tilted causing the pulley to rub funny at slow speed. We will give it another look. I posting another question about paper. If you have timeI place value on what you have to say
Speed issue solved. After 3.5 hours of adjusting the motor and finally getting it back to speed it had run before I FIXED IT we discover that we a actually running at 1800 rpm all the time. We had never timed it on repeated tests and thought the dial was correct when it read 2500 and would not go any lower, ( my mistake). We can now slow it down just below 2200 on the dial which is really 1820rpm. It is running a little quieter so the time was well spent. I hate when I fix what was not broke to begin with