[Magritte]

Any idea on solving an engraving problem on a rabbit 3040 running newlydraw via parralel port.

The laser engraves the image fine in then all of a sudden decides it going to move up or down and continues there with the image. I have been engraving some tiles fine for quite a while but changed to a new job with different size and image and this has been happening!

Any help it greatly recieved!

[Magritte]

I engraved the tile image much larger the 'problem image' without anything going wrong. So its not the image size.

I also tried the 'problem image' it as a .png .bmp instead of a .jpeg and it still 'jumped'.

Do Chinese laser have problems with larger file sizes? Buffering problem?

Any ideas?

[Philipf]

I have the same issue on a K40III laser. If I change the image to 72dpi I have more luck bit still only 50%. Does yours jump in the same place on the engraving, mine gets jumps in almost the exactly the same place but it also acts erratic going back and forth.

[ecpur]

I think the problem is the board buffering.
DSP System CO2 Laser Cutting Engraving Machine Color Display CNC

[belin]

i think the problem is in the switch settings on the stepper motors....

but im guessing with newlydraw which is similar to moshidraw that thw stepping motor drivers are built into the circuit board itself

one of the reasons i have just completed a perfect conversion to a DSP controller

if you guys have 2 individual stepper motor drivers as in the attached picture....try this setting on the little switches on each driver

you should see them listed as 1,2,3,4,5,6,

ok...Nos. 456 are the power switches of sort....set them as this

4=ON
5=ON
6=OFF

with switches 1,2,3 just play with them...move them to any positions you want until once your moving the arrow keys to move both axis that the machine starts moving smoothly....

sorry....i tried to add pictures but for some reasons it would not let me

NODDYS>>>HELP PLEASE

[Magritte]

It sometimes does it in roughly the same place. I am changing the file a fair bit to try and get round the problem. It seems to do image with just large blocks of black fine. Photos its really struggling with. I have decided to engrave one part at a time and then reset everything to empty the cache just to get this job done.

[Magritte]

i think the problem is in the switch settings on the stepper motors....

but im guessing with newlydraw which is similar to moshidraw that thw stepping motor drivers are built into the circuit board itself

one of the reasons i have just completed a perfect conversion to a DSP controller

if you guys have 2 individual stepper motor drivers as in the attached picture....try this setting on the little switches on each driver

you should see them listed as 1,2,3,4,5,6,

ok...Nos. 456 are the power switches of sort....set them as this

4=ON
5=ON
6=OFF

with switches 1,2,3 just play with them...move them to any positions you want until once your moving the arrow keys to move both axis that the machine starts moving smoothly....

sorry....i tried to add pictures but for some reasons it would not let me

NODDYS>>>HELP PLEASE

You mean the jumpers? I have 8 of them, I had a play around with them it made no difference unfortunately. I think the cache has mostly had it.

I want to replace the board really but its hard to find one that both cuts and engraves for a reasonable price. What is the DSP like?

Found this one below but I dont undestand how to convert a raster image to G code
http://electronics-shop.dk/?id=1061&currency=EUR

[dbtoutfit]

This can also happen because of the motor tuning.
You have Velocity and Acceleration.
Engraving smaller images, the Velocity doesn't have time to get to max speed.
Acceleration is how fast you can stop and go.
What happens is at (ie. 500 Vel) on small images your only getting up to say little over half the speed. When you stop and start to go back the other way the steppers acceleration settings are ok and the motors or setting is enough to slam brake and stomp the gas fast enough.

What happens when you're engraving and then it jumps and keeps on engraving is the steppers basically slip and looses position, their not on a closed loop circuit and have no encoders keeping up with their position.

So another words you need to mess with the Acceleration and Velocity settings.

Proof in point if you increase your speed from 500 on scan to say 1000 you'll see it happen very quickly and very often.

So if you're at 500 on scan then leave it and bump the acceleration up until it stops.
If adding more Acceleration helps then you can add more Velocity until it happens again.
For max speed do this back and forth. When you reach the point that no matter what you do to the Velocity settings it spins and looses steps you have maxed out your Acceleration.

That's the end of the line for your speed and you will want to slowly work back down your Vel and Acc trying to keep it at max with out missed steps.

Eric