Thread: Options for high positioning accuracy?

I've got to agree - for the most part I'm doing a one-off prototype, or iterating a prototype. If I were sending it out for 10 boards, I think I'd be inclined to spend a lot longer perfecting the design and layout, rather than just getting on and making a single board and testing and evaluating the whole system.

As you only wanted to have small work area why not just get a good engraver you can pick them up cheap then if you want upgrade it.

Saw this and thought you might be interested for making PCBs

Heatless (cold) Toner Transfer for PCB making - All

Thanks Rusel. Interesting technique, I'll have to try it next time I want to make something with really small components. I've found a lot of variance in the various toner brands when used for heat based toner transfer, with some performing better than others (and some not at all). That acetone + alcohol technique looks like it would work regardless. I'll have to dig out the etching chemicals and give it a run.

The part that was tripping me up was a SC70-5 package part, which had a gap between the pins of 0.575mm. I did get there in the end, but it took a suprising (to me) amount of fiddling. I ran into some issues with the board not being dead flat as well, which meant my v-bit was digging in deeper and leaving a much wider than expected track, which eroded the center pad and track. Honestly, I would have been better off going down to the local jaycar and paying the 4xmarkup for a 3.3v regulator (or the 50x cost increase vs the actual regulator I was using).

All the info posted here has been really helpful, and at least some of it will get used if I do decide to put together a dedicated PCB mill.

When I got to mill a PCB after not doing one for a while, I first surface the sheet of sacrificial MDF on my 6040, then stick the PCB stock sheet down with 2" double-sided tape beneath where I'm going to mill. I also try and zero the engraving bit right in the centre of the board area (using the electric puck). If I bugger any of that up, I start to get un-milled outlines of tracks, meaning I have to do another pass with a lower Z, increasing the cut width which makes the tracks narrower...

I do like that melting the toner with acetone technique, particularly in that you could use the same trick to stick toner to wood or plastic.

One thing to watch out for is if you use an HCL & hydrogen peroxide solution for etching, you need to make sure no acetone *ever* comes in contact with the H2O2.

yeah, i was thinking it would work really well for panel art.

I've been using an electronic probe to set the height, but I've been doing it on the edge of the board. Might change over to the centre for better results. My process is pretty much the same, but I use an offcut of whatever scrap wood clamped to the bed, and a pocket cnc'ed into it which takes the board. The double sided tape normally works well to hold the board flat. As I'm making pcbs fairly frequently at the moment I've also milled all the edges of the jig so I can use them as a reference and leave the jig clamped to the cnc.

I really need to sort out some kind of homing system so I can use set jig/fixture locations, since even with a single setup, Mach 3 forgets its X & Y position between sessions (there must be a setting for this - it makes no sense). I did start by fitting some proximity sensors to the Y (long) axis, but one of them flickers when the spindle starts, which could be a dodgy sensor, dodgy wiring, or I need to shield and earth my spindle cable...

noise put out by these chinese spindle is high. It will put false signals in any near by wires at some most inconvenient time of course.
I put a shielded cable and earthed the spindle body as well and added a waterproof plug. Found I could hear the radio not static and had no worries with the coolant.