Archive for December 17th, 2017

MPCNC: Pen Wobble

GCMC includes cycloids.gcmc, a test program producing a fixed set of hypotrochoids and epitrochoids, more commonly known as Spirograph patterns:

GGMC Cycloids test patterns

GGMC Cycloids test patterns

I’m using them to get familiar with bCNC’s Workspace Coordinate System settings and to exercise the MPCNC hardware; ya gotta plot before you can cut.

Most came out fine, but some showed distinct wobbles:

MPCNC - Cycloid wobble - star

MPCNC – Cycloid wobble – star

Tight curves and higher speeds produce more wobbles:

MPCNC - Cycloid wobble - loops

MPCNC – Cycloid wobble – loops

You’d probably never feed a wood router over 6000 mm/min = 240 inch/min, so this isn’t as much of a problem as it might appear. Also, I expect a few pounds of router will have fewer wobbulations than a weightless pen hung on a thin plastic mount:

MPCNC - Pen Holder Detail

MPCNC – Pen Holder Detail

Just one more thing to keep in mind.