Messages

1

Tangent Corner /

« on: February 07, 2014, 01:00:32 PM »

You could leave holding tabs when milling the first side, then cut (almost) right through when doing the second.

Alternatively, only do the radius and recess on the first side and do the whole cut out from the second.

2

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: January 26, 2014, 03:42:27 PM »

I've never heard of vellum for solder stencils. That sounds interesting. I've successfully cut Mylar with a 40W CO2 laser (an eBay special with a Chris Circuits controller board) but it did suffer a little from the edges thickening where it melted. Covering with masking tape (both sides) before cutting and some gentle fine sanding afterwards helped and and it worked fine.

Incidentally, how do you control the laser power using the S command? I'm thinking of doing something similar to mine - maybe adding PPI control from gcode. I'm happy to custom design a controller but still not sure how best to get the setting from Mach3 to my board. Modbus seems to be a bit outdated and need serial in addition to parallel. PWM isn't really what I need. Getting into plug-in development seems a bit over the top. Ideally I just want some data sent via a parallel port pin. Any helpful hints?

3

PoKeys /

« on: December 31, 2013, 01:51:45 PM »

Setting dir low worked for my MF70. Swapping the wiring is just as good a solution though.

4

General Mach Discussion / Re: Laser modulation signal?

« on: March 07, 2013, 11:02:59 AM »

Just switching the laser on at the beginning and off at the end of you vector cuts should do the job. That's what I'm currently doing on my 40W laser. The laser head is likely to be very light compared to a CNC mill so acceleration should be high and you'd have minimal ramp up. I'd try this first before going for a more complicated solution.

If you do want to make sure that the laser power doesn't vary with speed then you probably want to go with a fixed number of pulses per inch (or mm). This is an interesting discussion about this. I basically involves counting the pulses Mach3 outputs to the stepper driver. There's some trigonometry involved for diagonals/curves but essentially it's "fire the laser for a fixed time every N" steps.
http://www.buildlog.net/blog/2011/12/getting-more-power-and-cutting-accuracy-out-of-your-home-built-laser-system/

5

General Mach Discussion / Mach4 upgrade path

« on: March 06, 2013, 05:32:19 PM »

I work in software myself so I know how difficult questions about the next version are. I'm not going to ask for a likely date for Mach4 (although obviously that would be great). My problem at the moment is that I'm a hobby user and at the point where I can just about justify paying for the full version. What I don't want to do is pay for Mach3 just before Mach4 comes out and find I'm at a dead end. Also, being a geek I ALWAYS want the latest version even if I don't really need it.

No company wants to damage current sales with the prospect of a future version. What would be great is some assurance that a purchase of Mach3 today would get a free (or minimal cost) upgrade when Mach4 is out. Any chance of this?

6

Show"N"Tell ( What you have made with your CNC machine.) / Re: Laser cut titanium handcuff ring

« on: December 27, 2012, 04:45:51 PM »

I can't believe the first comments were about cutting the ring off rather than asking about the laser. As long as you have the tiny key on you then no problem! I wear a plain titanium wedding ring but won't worry about needing it cut off.

Fiber lasers are amazing. Maybe in a few years there will be cheap Chinese versions that us hobbyists can afford.