Question Engraving issues with SC 840

Hi all

Today I tested a few engraving jobs. However the results are not satisfying. I tried different speeds and feed rate. I think I found a good way. But I'm having a bit issue's in clamping and linear following lines etc.
Bellow a few pictures to see what I mean. Some paths are deep enough, other aren't. Do you guys have any hint on how to get better results?

Material: Polyester powder coated aluminium
Spindle speed: 21000 rpm
Feedrate: 150 mm/min
Plunge rate: 150 mm/min
Depth: 0,3 mm

Hi mathieu,

I'm a newbie but from pictures it seems that your cnc table is not flat. Check for flatness of you table.


regards

Jonathan

Yeah, I figured since engraving a line is not working well.
How should I check for flatness. How kan I make it flat. I have a T-slot bottom plate. I bought this one because I thought it would be flatter and more robust...

The T-slot bottom plate is mostly good for holding your material. The best way and in my opinion the more easiest, is to machine your material with your machine. I will use a 1.5m all over your work area. This will ensure that you have flatness. Than you can start your work.

Have you done it yourself? What kind of mill did you use? What settings?
I'm considering it, but I don't want to screw things up.

Hi Mathieu,

Perhaps invest in a dial indicator, similar to the one on the website attached.

www.inspection.ie/mitutoyo-series-2-metric-models-accuracy-177-13-181m-meas-force-1-4n-range-10mm-reading-0-50-0-remarks-l-h-r-c.html

You may need to work out how to clamp it in the tool holder and they are a little expensive but they do last forever, especially since you may only use it when you move your machine etc.

Put it in the tool holder, bring down the Z, zero the dial and move along the X and Y.

1) bolt sacrificial layer to the table in all areas so it can't move in the middle

2) skim the top of the sacrificial layer with the machine

3) then mount your work


4) use larger workpieces and use contact spray adhesive to hold the work down aswell..


Or... use a vacuum table system.. engraving laminated materials like yours is tricky. you want very shallow depth but you want detail... tricky.

other option is spring loaded floating head...

PS - this issue you have is not just with STEPCRAFT - its with all machines. Its always a challenge.