Messages

121

General Mach Discussion / Re: Spindle RPM

« on: July 19, 2008, 09:43:21 AM »

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=4550919
This is the switch in the UK you can view the datasheets on line.

http://www.alliedelec.com/Search/SearchResults.aspx?N=0&Ntt=slotted+optical+switch+917b&Ntk=Primary&sid=11B3A79D9029&i=0
This is the closest I could see on the US site.

The switch doesn't do anything particularly clever it's a light source (often infrared LED) and a photodetector often a photo transistor either mounted in an IR transparent package or has small lenses to stop cross talk etc. As long as it will run on the voltage you need and will provide a sink for the data pin (usual to put a pull up resistor on the output) you may also need to put a current limiter resistor on the feed to the LED depending on what one you get. Oh and ensure it will run at the max frequency you intend but this is unlikely to be a problem.
The thing I worried about is would the parallel port read it quick enough to get an accurate reading or would there need to be some electronic scaling but Hood has answered this one and fortunately it'll bolt straight on. I'll be trying to connect mine to the smoothstepper board (on order) which has a dedicated input for spindle speed (I think).

122

Mach3 under Vista / Re: mach 3 and vista

« on: July 19, 2008, 09:27:07 AM »

Sorry I forgot to mention I'd installed the memory override thing. I'm sure I'll get to the bottom of it when I've got a few minutes to fiddle. I was just curious about the icon thingy ie I could be doing something wrong in the mach installation or somehow getting an older version. I also thought after writting this that the pals version is probably registered and as I said mine isn't so maybe they change colour once registered. Thanks for your reply matey.

123

Show"N"Tell ( What you have made with your CNC machine.) / Re: some mach3 inlay work

« on: July 19, 2008, 07:33:36 AM »

Do you cut these on a 4 axis mill ? Do you cut out the inserts as well ? Some v good work there and the accuracy seems spot on no obvious gaps anywhere.

124

Show"N"Tell ( What you have made with your CNC machine.) / Re: RC scale airplane propeller blades.

« on: July 19, 2008, 07:03:11 AM »

Not being up on the terms, does the 'mesh' mean this was done with some sort of scanning then reproduction ? I would imagine this would be very tricky to do writing directly in G code.  Would you form the root of the blade whilst it was still in a block of wood form then clamp the root in your 4th axis and let it do it's stuff from there.  I've seen a few mentions of digitising probes and point clouds do these get converted from point clouds to g-code for reproduction or can they be cut directly from the point cloud ?  Hmmm more mystery's than knowledge on my behalf at the moment.

125

Mach3 under Vista / Re: mach 3 and vista

« on: July 19, 2008, 06:36:00 AM »

I have a problem in Vista the drivertest  thing doesn't run. I've done the install reboot thing and run as admin even though it didn't ask me to reboot. One question I've got is I've seen a screen dump from a friends PC and on it the icons for Mach 3 mill are in grey scales but mine are in colour. Does this mean mine hasn't installed the correct version or something. Mine isn't registered yet as I haven't finished building the CNC mill yet and want to get everythign working before I go the whole hog. Thanks for any insight.

126

Show"N"Tell ( Your Machines) / Re: My CNC Mini Mill and CNC Router

« on: July 19, 2008, 06:06:17 AM »

Great looking set up and you've done a thourough job with the log as well. Do you find the X axis sags  a bit ? If so do you need to do some cunning compensations not to ruin your Z axis accuracies ?

127

General Mach Discussion / Re: Spindle RPM

« on: July 19, 2008, 04:24:41 AM »

I suppose I'm still on topic with the this question. Now I've got my OPR probe sorted what do folks find works for controlling the spindle speeds? At present my 626 mill has only got the swap the ratios of the pulleys type speed control. I could rig up a thyristor fired motor speed controller but this would only give me a wider range per ratio or is there enough torque if the ratios are left on the fastest setting and just control the motor speed. How do you fellows do it ?
Thanks

128

General Mach Discussion / Re: Spindle RPM

« on: July 19, 2008, 04:16:12 AM »

Thanks for that Hood. It looks a simple enough addition and should give a pretty good clean output. Did you need any interfacing electronics? Are you coupling this directly to a breakout board or smoothstepper or what have you ? It looks like it's only £5 from RS so no point trying to build something myself

129

FAQs / Re: Laptop requirements with Mach 3

« on: July 19, 2008, 04:09:00 AM »

Yep if you use a breakout board with opto isolators they do a pretty good job at cleaning up the signals the other way is to run the signals through a schmitt trigger. Sorry I digress

130

General Mach Discussion / Re: Spindle RPM

« on: July 17, 2008, 04:27:18 AM »

Have you gents made your own once per rev probe ? If so could you point me towards any posts that discribe what designs work ? I have searched for the data but not much luck so far. Thanks.