Howdy folks,

After a few years of trouble free service I've run into my first "major" problem with my GCC Mercury 25W. Perhaps the issue is not major, but I'm not really sure what's going on. When I go to etch an image not matter the size power, etc., the etching starts to shift to the right the further I get down on the table. The first few inches at the top of the table are hardly noticeable, but by the time the etching is 6 inches from the top of the table, the image has shifted 3-4 inches to the right. For example, if I were to etch a 6x6" image that looks like this:

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It will look something like the following once finished:

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If someone has any ideas or can point me in the right direction, it would be very much appreciated.

Thanks,
-Mike

It is the X axis loosing where it is. If you have an encoder strip be sure it is spotless.

If you do not have an encoder strip, with the machine off unplug and replug all connectors that go to the X axis motor, it might help. Then there are always belts and pulleys.

Try reducing the speed of the machine, (of course reduce the power by the same percentage.) This probably will get it working for a while until you get a reply from the manufacturer's service person.

Philadelphia, PA (Really Bensalem)

When you finally understand it completely... it changes.

Exactly, the x axis is loosing it's positioing. I'm uncertain about the encoder strip, perhaps that is used with stepper motors. The Mercury is equiped with servo motors and it's my limited understanding that servo motors use a control loop to maintain it's positioing. This control loop may require tunning, but that is something I'm not familar with.

Well it appears my positioing probelm is not a consistant shift like I was explaining. I just ran a file with Mike typed a number of times lined up one on top of the other along a perfect y axis. As you will see in the attached file, the x axis positioning is all over the place.

A servo motor uses an encoder to determine position. It can be a strip (like newer Epilogs use) which is a glass or plastic strip running the length of the X axis, or it can be a rotary encoder built into the back of the motor. If you can't find a long straight strip, it's probably an encoder on the motor. Those are usually sealed and except for a loose wire they usually can't be cleaned. The long strips are usually exposed and need to be cleaned.

Steppers don't need an encoder, though a hybrid system can use both an encoder and steppers.

You might also check the X axis rails to make sure they're clean, and whatever runs on the X rails is in good shape (rollers, a slide, linear bearing, etc...)

Servos use a closed loop to control speed. There must be an encoder in the circuit to report the position to the electronics.

Most often we hear here about an encoder strip along the X beam that gets slightly dirty. It may be hidden under a shield in order to try to keep it clean.

Philadelphia, PA (Really Bensalem)

When you finally understand it completely... it changes.

Mr. Mike,

That photo looks like what was going on with my machine when the bearings/belt needed replaced. Hope you find an answer quickly.

~

Is the replacement of the belts and bearings something you did yourself or did you have a tech do it?

Thanks,
-Mike

I replaced them myself.............. I have a different brand machine than you.

so, "you're mileage may vary, price does not include sales tax, as seen on TV".
:O)

Call your mfg. and they should be able to diagnose it and get the proper parts on the way to you, then help you with the install.
B-)

~