There've been numerous discussions about this very subject in the past on this site. You can do a search if you like. Some will argue that their plotters don't do that, but I think all friction feeds do.

One solution I've found that works really well is to apply paper transfer tape to back side of plastic back. (Mentioned previously by I don't remember who. What they said to do was apply tape over entire back.)

All you have to do is apply those 1.5" to 2.5" (just guessing on actual width) strips you usually get as samples from suppliers along each edge. Just apply length you think you need. It really keeps registry tight on multi-colors. I use the conform stuff.

Hope that helps,
 

Karen

[ November 05, 2001: Message edited by: Karen Stein ]

You should also contact them :
Summa
directly. They could help you.

[ November 05, 2001: Message edited by: Steve Shortreed ]

Sorry to be slow to respond ... I had referred this question to our tech folks in hopes someone would respond, but am jumping in since no one's gotten back to you yet. You can e-mail our cutter specialists at allenh@summadirect.com and/or support@summa.be.

My own experience with ploy-backed 3M has always been no problem. Our premium DuraChrome / Summa DC2 media is poly-backed 3M, and I've never had an issue with media-out sensors not reading the film, either contour cutting or working with small scraps. Hence, I suspect the sensitivity of your sensors may be set differently. I just don't know if I'm right, or if it's an addressable setting (it is with the OPOS sensor ... I'm guessing on the media-out sensors). When I know more I'll post it.

Also, please call 800-323-9766 to speak with our tech folks directly.

Thanks,
 

Man! Tough questions in this thread. Did I mention that I'm a marketing guy? In other words, I talk about problems I don't understand, and make them sound like benefits

I'll get one of our tech guys into this discussion pronto. They do know what they're talking about, and tend to use less varnish.

Meanwhile, I'd advise cleaning the drive drum. Turn the sticky side of some scrap vinyl upside-down, lower the pinch-rollers, then pull the vinyl back and forth. That may help. If not, I'm stumped, since trimming the edges of the material has traditionally been the solution with thicker sandblast resist.

Best Regards,

Jim

[ November 07, 2001: Message edited by: Jim Doggett ]

To prove my point try this experiment. And please use materials which you have purchased. That way you'll understand what it feels like to have invested time & money into an effort that results in wasted materials.

For this example, using design software of your choice, create a line of copy approximately 5 feet in length. Make letter height about 3 inches. You can use all upper-case but I'd
prefer you use upper & lower-case lettering.

Got that? Now, create an outline of say 3/16" (or .188). Measure & write down dimensions of graphic exactly as shown in software program. Pay particular attention to the length. Record both the original copy dimensions & the outline.

What I'd like you to do now is cut the outline (this would be as 1 solid, fat letter to underlay copy placed on top later)using black vinyl with paper backing. Next, you'll cut the color of your choice, for the original copy, on any plastic-backed vinyl you choose. If you want to, you can use SignGold.

Now comes the fun part; & to make it interesting, let's use banner material as the substrate. 1st, apply the black outline. Then apply the plastic-backed copy.

Well, how does it look? Everything match up OK? If it does, you've proved your point. If not, then I've proved mine.

(You have my permission to print this & use as a guide although you may have to get approval from the Mayor).

Just try it. That way we can simplify this discussion.
 

I haven't done your test, but honestly, I've never had tracking issues with our 3M poly-back media ... using our cutters.

Where I believe inaccuracies would be most evident is with contour cutting. At shows we'll take labels that are printed on the DC2 (and previously the DuraChrome), and contour cut them on an OPOS-equipped Summa cutter. I leave some border offset around the labels for appearance purposes. But, to demostrate accuracy, I print the contour line in a faint yellow hairline to show that the contour cut is spot-on. That simply can't work unless everything is super precise -- the OPOS, the tracking, everything.

I've got to think that something else is a play ... Allen in our support will wiegh in here soon. He's in the middle of another project, and I didn't want to take him off-task.

Gray, Brian, when I spoke with Allen he said that media-out sensors ARE sensitivity adjustable! He'll explain further here ... soon. But that'll correct Gray's length reading in SignLab, and Brian can pull the tape off his sensors.

Best Regards,

[ November 07, 2001: Message edited by: Jim Doggett ]

There are three specific problems being discussed here. I'll address each with a specific post. First I'll talk about the inconsistency of cuts. Here is why you are having problems matching the output from plastic backed material and paper backed material. The following explanation is in reference to the “gold grit rollers, the material, and length of cutting” in a Summa Cutter.

In your mind please picture a circle (this is the grit roller from a side view). Now the radius of that circle (grit roller) is from the center to the top outside edge of that circle. Now if you add on material to the top of that circle the “radius” becomes larger. It now goes from the center of the circle to the top of the MATERIAL. Different materials and backings have different thickness. So the thicker the material the bigger the radius becomes, and the rotation of the grit rollers is going to be different for each thickness to get the exact same length in a cut. I.E… thicker materials need more rotation (of the grit rollers) to move the same amount of material. Plastic and paper may seam like the same thickness and both do function but even the slightest thickness difference in a backing can show up over extremely long cuts.

Good news is our Summa cutters have a feature called “Calibrate X-Y”. Using this calibration you can calibrate your Summa cutter for a specific type of material. The cutter is calibrated from the factory using 2mil –3 mil thick standard vinyl. So people that run other material like sandblast, rubylith… tend to see this problem more. Please if you are attempting to do this give us a call first at 1-206-527-0447 or 1-800-323-9766. What I recommend doing is pick the material that you use the most or that you need the absolutely MOST accurate.

The reason is you can only calibrate the cutter for one type of material (without having to recalibrate each time). Then run the “Calibrate X-Y” using that specific type of material. After you’re done the cutter will be dead on when using the material that you calibrated it with. After calibrating the cutter send a box from your cutting software to verify that the lengths match up. If they don’t the calibration was inaccurate (see below).

NOTE: the cutter will only be as accurate as you are. If you can’t read a ruler, if your ruler is inaccurate, you can possibly make the cutter worse than it already is. Your accuracy when calibrating is going to be directly reflected to your cuts. I recommend setting the cutter to Metric to do the calibration. It is much more accurate than the English system.

[ November 07, 2001: Message edited by: Allen ]

All my post intended to point out was that I have never had any problems with slippage, or misalignments as long as I used like materials going thru the plotter. My little Summa is one fantastic machine and tracks all day long without a misstep as long as I load it properly and feed it like backed materials. Henry, I did experience some of what you experienced with running Stencil material thru the T750. Several things come into play here...weight of the material, width of the material, plotting speed and the fine powder coating that is applied to the sandblast stencil.
On my 24" Summa, I can honestly say I've never had a problem with stencil slipping or going off track on a long run. At the company I worked for in Az, I used a T750 and of course, we used the 30" material. It was a constant hassle, but I learned some tricks to get around the problems. When a new roll of stencil arrives, I roll it out and completely wet wpie & dry the whole roll to remove the powder that it is packed with (this stuff really contributes to your rollers getting gunkie fast = problems. Then I re-roll it the opposite direction that it came...seems to feed thru better that way. I set my speed down to about 2 and then if it is a 30" roll, I either set it up so that it rolls off & onto a table at that height (to decrease the drag...long spans of this stuff at the 30" weight are really quite heavy..of course this would result in slippage)or, for that particular long run, I babysit the plotter and hold the material as it feeds thru the machine. This eliminates almost all of the problems with the 30" stencil tracking properly. You have to remember, there is a heck of alot of drag force going on here...makes it worse if your blade isn't really sharp too. Yes, you can rin either application tape or a line of masking tape down the sides for better grip, but I found that just cleaning that powder off the plastic solved that problem. Personally, I think the bottom line with the tracking issue on the T750 for stencil is the added weight of the material at 30"..as I have cut a ton of stencil on my 24" D610 for years with no problems at all. Maybe it needs an extra pinch roller or two? 30" is a pretty big span with heavy floppy material.
Bill, you sound disenchanted with friction feed plotters in general...they do have limitations, but the Summa company for one, IMHO, has never claimed Summa plotters could do things it can't.
I've run plenty of sprocket fed plotters and they also have their limitations and can go haywire and eat up alot of material too. They are all machines. People are ultimately responsible for how effectively they are used. Granted, along the way, some minor adjustment might have to be made to a sensor or something, but if you take care of your machine, keep it clean, sharp blades, make sure you use like materials,& clean materials...you shouldn't have any problems.

OK, I'm finished now
Karen
 

Your problem is different than the current one so I hope you don’t mind me addressing it separately. (Btw... sorry Jim for the delay in helping out all these customers... blame the Nimda virus)

Jim is correct in that our Summa brand cutters have specific sensitivity settings that you can change to detect different (difficult) material. I would recommend contacting us directly so we can give you a bit more personal help in setting up the sensors at 1-206-527-0447 or 1-800-323-9766.

In the mean time here are your options: First, you could turn off the sensors. This will allow you to cut any type of material that the cutter would normally not sense, however there is some down side to this method. If you run out of material the sensors will not detect the absence and the cutter will continue to cut the rest of the job on thin air, and the protective cutting strip. Covering the sensors with tape is the same as turning them off.

The second method is changing the sensitivity of the sensors. To do this you need to scroll to “Sensor Setup” inside the cutter. When you start this calibration on the LCD you will see 2 arrows. One arrow pointing to the back of the cutter, and another arrow pointing to the right side “>”. The arrow pointing to the back of the cutter is the physical setting of the media sensors. To detect your difficult material you will need to move that arrow farther to the left. Using the arrow keys move it 1 spot over to the left and make sure to press the ENTER button on the cutter to set that value (enter is the “V” button on the SummaCut D60’s). After you press enter back out using the “Hand” button on the SummaSign cutters, or the “X” button on the SummaCut D60’s. Try inserting your material, if the cutter detects it your great, if not try moving that arrow farther to the left. Again please contact us or one of our dealers if you wish to change your sensor sensitivity for a more accurate description.

[ November 07, 2001: Message edited by: Allen ]

Ok now for the last problem, and that is material slipping or miss tracking. Karen just said it so precise I’m just reiterating that post from a tech view. “Thanks Karen you said everything and more that I was about to type”.

For the Summa cutters and all friction feed machines it is EXTREAMLY critical that you keep your cutter clean. If you took a close up view of those gold grit rollers, they are hundreds of little pyramid shaped objects around a drum. If dirt, debris, vinyl, glue, powder (from sandblast material) get in the empty spots between the pyramids then the cutter can start to loose tracking. Because the grit rollers can no longer hold the backing like it normally should.

As an example I would say that 95% of the cutters that come in for tracking problems are ONLY caused by the filthiness of the cutters. After we clean them up (sometimes a 5+ hour job … yuck) they work as good as brand new cutters. I correlate this to cars … if you buy a car and never change the oil, never do any maintenance to it… eventually the car will blow up! If you do all the maintenance, change the fluids, etc... That car could last you decades or more. The same goes for cutters and any other mechanical device.

To maintain the tracking there are 2 main things you should consider one is the cleanliness of the grit rollers and pinch rollers. The other is the type of material you are using. First, to clean the grit rollers or pinch rollers: POWER OFF THE CUTTER, take some strips of vinyl and remove the backing. Place the “sticky” side towards the area you want to clean (down for the grit roller, up for the pinch rollers). Lower the pinch rollers and manually roll the material back and forth to pick up and clean the dirt from your cutter. **DO NOT CLEAN THE GRIT ROLLERS WITH ANYTING ABRASIVE**. Also the pinch rollers do wear down and should be replaced if cleaning the cutter doesn’t work.

The backings of the material both have negative points to them. Paper is very good but if you run at extreme speeds it is brittle and the grit rollers can “rip / cut” through the paper. Try to lower the speed down from full speed to maybe 80% (lower if you still have problems). With plastic material it can be hard for the grit rollers to grip it when they get dirty. Also it is a slippery material so speed can affect this type of backing as well. If everything is clean and working, loaded correctly, and the roll of material is wound strait, the cutters can track rolls of material with no problem. ** I personally have tracked full 50-yard rolls non-stop; both paper and plastic backed testing cutters. One of our customers boasted he did a run of 600 feet / 200 yards of paper non-stop on one of our D120 SummaCuts**.

Thanks all,

[ November 07, 2001: Message edited by: Allen ]

Thanks for the tip on Hartco. Now I really owe you a beer in AC. I was hesistant to suggest it, since we are a Hartco distributor. And I hate to waste my non-objectivity on anything but our equipment

And no, you can't have Allen. The 13th Amendment not withstanding, he's indentured to Summa

Regards,
 

So, it's agreed that different backing & thickness of vinyl products will affect size of cut material. But the good news is it can be corrected thru software settings. The only thing
I was disgruntled about was, in the past, nobody would admit it.

Thanks Jim & Alan for your quite informative responses. I knew you could set parameters for different materials used, but never considered making adjustments to X & Y movements. That's good to know.

I found this problem early in my plotter's life. (It wasn't used enough to get dirty.) I was preparing to letter a tow-truck with 3 colors. (lettering with outline & drop shadow)
Everything was laid out & ready to go. I was just waiting for the electrocut to arrive from that place that isn't a Letterville Merchant. The garage owner had already called & wanted to know when to expect me. The (ec) arrived (normal June weather - not hot or cold - just right) & I cut all the graphics. It was upon trial registration that I discovered the problem. My quik-fix was to measure the difference between the registration blocks & add that amount to length of (ec) & recut. That worked ok but I
knew there just had to be a better way.

It's nice to know that you (at Summa) have all the parameters figured out for the different materials & backings. Could you email them to me? I just need the corrections for Electro-cut,
SignGold & Shadowlook(Trendfilm). No hurry.

Thanks,
 

"Why do my letters not always match up perfectly with the outlines".

I never would have thought of the difference in thickness of vinyl and/or liner affecting the circumference of the grit rollers.

It is nice to have someone add some logic to things!
 

I think its a great credit to Jim and his team, that we can openly discuss "operational problems" openly without anybody taking it the wrong way. So many clitches today in hard & software are brought on by ourselves or the conditions we work in.

I am more than impressed with my T750, just was unsure about the "slipping" with sandblast media. But Karen you make some great points which Allen backs up. My machine is a year old so not really hammered as yet but I know what you mean about the powder on anchor and will re-roll the media outwards instead of inwards. I use a new blade that is reserved just for sandblast, and the steeper angle to the standard.

Howard you make some good points, the Anchor I use has a "tracking edge" just plastic without sandblast resist on it. So I try to keep the rollers on that edge.

I used Hartco sandblast materials previously and think its much better in my enviroment than Anchor. I had to buy it from England as there was nobody selling it up here, and now the British pound has gone so high that it makes it a non starter...which is a shame. I have a supplier to the monument stone industry here that sells Anchor so thats what I have to use today!

Dave I once remember my local Gerber guy telling me how accurate the old sprocket machines are against friction. So as a shop thatdoes alot of multilayer graphics I wondered why things never lined up right. You put a shadow down first and then if it was a 6 or 8 letter word, would have to split it in two to get better registration.

I called Gerber one day and they said if you bought all media from the same source this would reduce this. It was down to converters punching holes at different speeds, strectching slightly.

I have never had a registration problem with the Summa machine.....that said I would not throw out the 2 old Gerber workhorses behind me either!
 

I hope I didn’t miss lead you, we don’t have specific settings that you can just enter in and make it correct for any type of material. Due to backings, age, cleanliness, each cutter over time has different calibration settings. First thing to do is clean the cutter, then after you clean it if your still not satisfied with the accuracy do a X-Y calibration. To get the exact cuts that you want with a specific type of material you have to insert that material into your cutter and run a “X-Y calibration”. Remember that the cutters are already calibrated (from the factory) for standard 2-mil, 3-mil vinyl.

When doing a “X-Y calibration” the cutter will cut 2 lines on your material that look like a large +. The horizontal left to right line is called the “Pen Axis / Head Axis” the vertical front to back line is called the “Paper Axis”. After it cuts this large + on your material, the cutter says “Press 1 to measure, 2 to abort”. Press the number 1 button on the cutter to tell the cutter you wish to measure the cut lines. Remove the media and physically measure the lines.

On the LCD of the cutter it will display a number (in inches or millimeters depending on what you have the cutter set for, preferably metric do to the greater accuracy). Using the arrow keys on the cutter change this number from what the cutter thinks it cut to what you physically measured. Press the enter button to go to the second line and do the same thing. Now the only line you should really have any discrepancy’s on is the “Paper Axis”. The “Pen Axis / Head Axis” is 99.9999% never going to change (it just goes left and right).

After you run the calibration go to your cutting software and output a box or line and it should match up (If you calibrated / measured it correctly). NOTE: The cutter will only be as accurate as you are. If you have any doubts about your accuracy it might be best NOT to do the calibration. Hope that clears up the “X-Y calibration” a little more than my first post. If you have any questions about running a calibration please feel free to give us a call.
 

You've been most helpful & informative. The only question I have & I ask it because I have the same plotter as Gray, is that because the D620 doesn't have an LCD screen, can these calibrations be performed thru software?
 

Yes, all setting can be control thru Cutter Control ... frankly much easier than the on-plotter control panel. Just scroll thru the User Settings until you see the parameter you with to adjust.

Reagrds,

Jim
 

Much appreciated.
I'm done.