Reply To: Chatter cutting 4mm plywood

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#39171

Azza
Participant

Hi,

I’ve build my own 3d printers. I’ve basically got 3 machines, a Prusa i3 which built the Kossel Delta and that printed me a MPCNC.
They’re all RAMPS 1.4 hardware. I’ve got plenty of parts / spares etc. for when the magic smoke escapes.
I pretty much know my way around 3d printing, calibrated etc. the hardware, firmware etc, but CNC is new to me.
Steps are set correctly on XYZ axis, although I’ve not done fine tuning like I would on a 3D printer to get the dimensions super accurate.
From memory the machine is approximate 800mm x 800mm with ~150mm Z.

The bit is a 3.125mm ballnose, running 12000RPM (max speed of the spindle). GCode came from ESTL CAM.
I started with 1mm depth per pass, dropped it to 0.5mm to see if it helped. It did a little bit.
The is a picture of the machine before it went into the Shed.

IMG_20170423_193356

This is what I’ve made using 6mm plywood. Dimensions are correct otherwise it wouldn’t have slotted together.

IMG_20170627_201904

I’ve been clamping the plywood to a 3/4 inch sheet of MDF to see if that helps.
Seems the plywood I’ve been using lately is harder that the first sheet… or at least the vibration is only bad when it breaks through.

Sorry will have to get a picture later. I’m a bit stuck for time to investigate as I’ve got young kids and its a struggle to do anything.
This is a photo of carving the toy parts – I was pretty slack with the clamps but it was happy with that material.
The second sheet of 6mm ply I bought was much harder and I started having issues with that.

Thanks for your help. The machine is a great design.