GS 15 plus alignment problem

[Tel]

Hi Folks
I operate an edge and use an old GS15 plus cutter in conjuction with it, I am having a small alignment problem, if I print and cut for example small circular stickers approx 1 inch diameter and can get 10 stickers in the width this is what happens on one row, the first circle cut will be fine then as it goes across the carriage the cut moves slightly off to the left side and after it passes the centre it starts to come back but never gets back to perfect like the first one cut, the stickers in the centre are the worst, the next row will be the same the first sticker being fine again and then drifts off to the center and comes back again towards the end.
My thoughts are that maybe a previous owner has carried it about by the wayshaft or it has been leaned over on its wayshaft and that the wayshaft is slightly bowed.
I have some knowledge of gerber tangential cutters and can do all the adjustments X, Y and Z and drum end float, I have replaced theta belts and drums before. As far as I can see all securing screws are secure an all adjustments correct. I think it is something I have to live with until I can get a new cutter.
Any thoughts would be welcomed.
best regards
Tel

 

[Tony Teveris]

Are the sprockets clean, any streaching of the vinyl hole pattern?

 

[Fred Weiss]

Four suggestions ...

1. In addition to what you mentioned as to the adjustment of and condition of belts and such, make sure that the plotter is well cleaned and lubricated. Gerber plotters are built like tanks but are susceptible to erratic cutting when not regularly lubricated. In particular, one drop of light oil should be placed in the throw out bearing every six months. This port is located inside the tool head and you don't see it until you rotate the shaft 180 degrees.

2. When you create your repeats, always create the vertical nest in Composer and the horizontal repeats in GSPPlot.

3. When you produce the job, set your target to the center position, set print to center on page and uncheck the box to "Conserve Foil".

4. When designing your artwork, use chokes and spreads as well as bleeds whenever possible to create error tolerance. An error tolerance in color to color or print to cut registration of + or - .020" is normal.

 

[Tel]

Thanks for the advice Tony and Fred.
The sprockets are good no stretching of vinyl holes. I reguarly oil and clean the cutter I learned that from you a long time ago Fred, I will try all your advice and let you know how I get on. I do use choke and spread and bleed but I have never set up the repeats as you advise and my target is always lower left.
Best Regards and Thanks
Tel

 

[Tony Teveris]

TEL,

You could also try the calibrate test. If I read this right, the error is in the y-axis, which means something may be up with the belt. It's worth a try. You should print CALIBRAT.PLT on your Edge, and cut it on your plotter. If the belt is good, and you have lined up perfectly on the target, you should see cuts align at the top and bottom of the J10 box. If you punch in what you see, that will set a Y scale factor that will be used to adjust the data going to the plotter.

 

[Tel]

Thanks Tony I'll try that
Regards
Tel

 

[Tel]

Just ran the Calibrate.plt test, the lines that line up for me are at the top line 5 and at the bottom it is J. I am not sure where I punch this info in, or is that telling me something about the belt, I will have to get the covers off and check the belt again I assume
Regards
Tel

 

[petepaz]

if all of the above doesn't work you need a tech to check it out. we have had our plotter for about 10 years and like fred said it works like a tank, it's been through many wars..haha. but i had a similar issue once that all the cleaning and lubing didn't cure it and i don't know what they did but our service tech fixed something cost us $200 but well worth it for all the work this thing has put out

 

[Tel]

At home now, but I remember know how to do the calibration, I select calibrate in Device select and put my information from the calibration test in there. Sorry to say this petepaz but I'm in Northern Ireland and as far as these older gerber plotters go I have no faith in any of techs here they have never solved any of my problems, I have always got my solutions from here and mostly from Fred and Tony. I have no doubt that in the USA your gerber techs are up to scratch.
I just love working with tangential cutters find them fascinting, also use a couple of Graphtec cutters, and a Tekcell router which I will be on most of the day tomorrow, but I love the edge and GS15plus.
Best Regards
Tel

 

[petepaz]

that's great if you can handle all that technical stuuf and tony and fred are the guru's no doubt( i think they bleed gerber...haha)
good luck either way

 

[Tony Teveris]

The calibrate button is in the Plotter/Printer Select dialog in GspPlot (on the bottom).

A dialog appears where you select the config of your best alignment.

What this all does is change the y axis scaling factor for all you cutting, It ends up being a very small scaling and assumes the error is linear.

Remember if you do this and it does not work, or you go changing something else that would effect the cutting (belt, roller, etc) I would revisit this dialog and reset the selection.

 

[Tel]

Thanks Tony I have recalibrated and it is certainly better except that if you can imagine the cut across the carriage goes like a bow, on these small circular stickers the first in the row is perfect the last one now which is the tenth is almost perfect but in between it drifts slightly to the left as it gets to the middle then goes back to the right bringing the last cut almost perfect now.
Thanks for all your help I can live with this now it's calibrated.
Best Regards and Thanks
Tel

 

[Tony Teveris]

Depending upon which direction is off (-/+) it sounds like there is an unequal amount of pressure during the printing where the two ends have the same and the middle has either too much or too little. Just a thought.

 

[Tel]

Depending upon which direction is off (-/+) it sounds like there is an unequal amount of pressure during the printing where the two ends have the same and the middle has either too much or too little. Just a thought.

Oh I see I might be looking at the wrong machine the problem may be in the edge. I will give that a good look at, although I was doing a run of stickers this morning and was really satisfied with them although they were at least double the size of the ones I had problems with and were not circular but rounded rectangles.
Thanks for all your help
Best Regards
Tel

 

[Tony Teveris]

Another thing is try slowing down the cutter (20% speed) - I know its slow but give it a try.

 

[Tel]

Thanks Tony will do
Best regards
Tel

 

[Tel]

In conjuction with setting up the stickers as Fred described and the calibration etc advised by Tony I am now satisfied with the cut I am getting on these small stickers, I have had to do a few sets for customers this week and they have been delighted with their stickers, I can however still see a slight bow but as I now set the target at the centre the result is that the stickers either side of the centre are perfect then they drift a little off towards the ends and it's the same both ends but it is a very small amount and we are satisfied with it more to the point our customers are happy and don't even notice it, maybe I am being to fussy.
Thank you all for your Help
Best regards
Tel