New member from Farnborough

[Doddy]

Evening all.
I have bought some professional cnc cut panels, and am looking to create many ancillary pieces for use throughout.
My first task is to see how viable it is to engrave some small pcb's, circuits containing 20 or so components. I have the files in Eagle and am hoping to compose Gcode within Mach3 to create these.
Regards Kev

Eagle ships with a PCB-GCode ulp which should be enough to feed directly into Mach3, assuming you mean to make the board with isolation-routing. My own experience with a cheap router wasn't particularly encouraging but you need to look at the capabilities of your own machine. There's two similar techniques - using V-engraving bits which requires a flat bed and little deflection on the spindle over the span of the X/Y axis (something than my Marchant Dice machine couldn't manage), or if you can't maintain an accurate height due to deflection then using micro-mills with straight-cutters in the order of 0.2-0.4mm dia - fragile as flip, and pricey, but they offer a better quality of cut. Best bet, use Eagle to export a design with some basic geometric shapes - maybe a square containing a circular path and try routing that on some cheap FR2 board (you'll probably want to use FR4 later, but for now FR2 will lessen your tool-wear, and is a bit cheaper whilst you're busy snapping bits). Work out how accurate and repeatable the machine can cut (maybe better to hand-craft some gcode for that) to understand how able the machine would be to route a PCB.

For panels, you might want to look at foamex and similar low-density board materials in the first instance and tentatively look at more rigid materials.

[Gkkes]

Thanks Doddy
I've been reading today many varying opinions on this forum, both on the practicality and competence of my investment, and as to the most successful way to approach the task.
I have found Autoleveller and many other suggestions as to type of bit, to drill speeds.
The cockpit will require many parts from wood, Perspex and possibly aluminium. The 3020 came with a discarded attempt in 1mm ally which looks very torn, so I don't underestimate the likely failure rate.

My current task, the throttle quadrant will loosely follow the method developed by Dave Allen over at 737flightsim

[Gkkes]

Double post. Sorry

[m_c]

I wouldn't even consider trying aluminium with a standard 3020.
BTW, you've got a 3020T, the T being for Trapezoidal leadscrews. These are less efficient than a ballscrew (a Z instead of a T on these denotes ballscrews), and will usually have more backlash (free play).

Spending some time on the 3020 would improve it, but you'd need access to some measurement tools, mostly a DTI (Dial Test Indicator) so you can measure and locate backlash.
If the T version is anything like the Z version, a basic improvement is replacing the bearings used to control the leadscrew end float, as on the 3040Z I bought, these were complete rubbish. Tightening to remove play resulted in very notchy movement, and loosening them of resulted in very noticeable play. New bearings, and careful adjustment let me reduce play to well under 0.1mm, which was good enough for what I use the machine for.

[Gkkes]

From the start I want to learn how precise the machine is by installing a pen refill instead of a bit, and "drawing" the design on some reasonably thick card, double-sided to the sacrificial bed.
Comparing measurements will identify errors in my method, design, code in both path and depth and instill an understanding of exactly how the eagle interfaces with the mill.
This might also highlight the deficiencies in the 3020T and provide a before/after comparison.
Enjoying the learning curve and brain workout.
My eBay search is still operational.
Thanks for continuing advice.
Kev