GS-15 problem

[Eric H]

Hi folks we have a gs-15 plotter that not turning the knife correctly during the job. It starts out ok but it starts dragging it sideways or backwards. It is not the timing belt or rotation sensor. If you push reset it turns the blade back to the correct location. Any ideas would be helpful.
Thanks

 

[Cross Signs]

New theta belt needed...about $80.00

 

[Eric H]

We just replaced that a few weeks ago the new one looks fine.

 

[Fred Weiss]

When you replaced the belt, did you reset the home position of the blade?

 

[Eric H]

Yes it was reset and worked fine for a few weeks. It is a similar problem but I don't think it is the belt, what else can cause similar problems?

 

[Fred Weiss]

Yes it was reset and worked fine for a few weeks. It is a similar problem but I don't think it is the belt, what else can cause similar problems?

It could be anything that is preventing the blade from starting in the home position and then following during the cut with a clean cut. I would check the following:

• Home position is correct. Turn on plotter with vinyl in machine. Look at the blade position. It should be positioned with the trailing edge of the blade in line with the feed in side of the plotter. Send a small rectangle to be cut to see if the blade delivers a straight smooth cut. If it doesn't and doesn't appear to be in line, then you need to reset the home position.
• The pink, knobby theta rotation belt is in good condition and has the correct tension. Remove the toolhead cover and inspect the theta belt. When squeezed together, the belt should have about 1/2 inch give in it.
• The toolhead is lubricated. On the underside of the main bronze bearing in the toolhead, there is an oil port which is supposed to have one drop of machine oil added once every six months. Rotate the toolhead until it is exposed and add a drop of oil.
• The blade is in good condition. Gerber blades are carbide which is very durable but also very brittle. They can chip just by being used when the home position is not set correctly. After you determine that everything else is okay, try a new blade.

Resetting the home position is done by:

• Unplug plotter and remove the end covers.
• Rotate the toolhead and follow the motion to a collar clamp which should be temporarily unclamped.
• Turn on plotter and allow it to seek home according to the sensor.
• Manually lower the blade until it touched the vinyl and slew the vinyl to the left. The blade will follow into an in line home position.
• Tighten the collar clamp.
• Perform test cuts.
• If okay, unplug and replace covers.

 

[Eric H]

Thanks for the help Fred. The theta belt is brand new and the tension is good. Home position is good it will even plot some before it gets out of rotation, and once it is out of position pushing reset puts it back at the correct spot. The round sensor disk with the slot on it is in the right location. The setup we have has been the same for years nothing has changed. Could it be a communication error between the computer and plotter? I am thinking more electrical than mechanical.

 

[gabagoo]

I may be way out to lunch here but......

I remember way back on my old 4b (man thats a long time ago) that we could get the odd problem with the blade and it usually was some of the perfed vinyl dots that did not get punched out correctly could get stuck on the belts and then somehow make its way into the gears inside and cause havock. Like I said I am probably wrong. lol

 

[Fred Weiss]

Thanks for the help Fred. The theta belt is brand new and the tension is good. Home position is good it will even plot some before it gets out of rotation, and once it is out of position pushing reset puts it back at the correct spot. The round sensor disk with the slot on it is in the right location. The setup we have has been the same for years nothing has changed. Could it be a communication error between the computer and plotter? I am thinking more electrical than mechanical.

Pretty sure all the theta rotation handling is done in the firmware of the plotter. Not likely an issue outside of the cabinet of the GS-15. Assuming you are correct in your statements, you might want to see about whether your firmware is up to date and not corrupted. After that, you would be looking at the electronics as a possibility.

We operated Gerber's 15" plotter series starting with a Signmaker III through to SuperSprint and HS-750. 99.9% of the problems we ever had with them were related to clean shafts, lubrication and things like theta belts or chipped blades.