Messages

151

General Mach Discussion / Re: Mayday, mayday, mayday: Steppers thumping and banging and losing steps

« on: May 24, 2010, 08:37:02 AM »

Hi Hood, thanks for the suggestions.

Sorted it ... it was a fresh install, and the parallel boards i was using beforehand (MosChip items, very robust).

the problem turned out to be USB things again - I could make it crash by scooting the mouse about. It seems WXP prioritises USB demands over anything else, legacy ports in particular, and therefore any USB activity (even routine polling for changes) causes a machine crash.

Solution: disable all USB systems and use a PS2 mouse and kb. While I was there I stripped out the soundcard, network card and usb PCI card. This releases a lot of memory and lowers the amount of possible interruptions.  That done, it now interpolates helical paths at 1800 mm/min with only 24% buffer load. I think it could go a lot faster

this USB thing has been a persistent problem ... any ways round it?  occasionally I need to get things on or off the mill.

152

General Mach Discussion / Mayday, mayday, mayday: Steppers thumping and banging and losing steps

« on: May 24, 2010, 06:41:04 AM »

Trouble at t'mill! I replaced the computer after the frost killed the old one off, and now it really won't play. 

It's a faster computer (1.5ghz Athlon over the 900mhz Pentium) and when jogging, with a 45khz kernel, it will easily drive at 2000 mm/min plus. However when executing G-code commands the buffer instantly exceeds 100% and the pulse train goes nuts, causing severe amounts of lost steps. I'm down to about 1200 mm/minute maximum now, and when executing a long, slow helical move it still loses steps, and the steppers thump and stumble.

Any common reasons why this would happen? I'm going to be in trouble if I can't get the beast dancing nicely, so any help offered would be sincerely appreciated. Thanks in advance

153

Show"N"Tell ( Your Machines) / Re: My Big Project am I crazy

« on: March 04, 2010, 04:54:10 AM »

Awesome machine! what a catch. I'd be interested to know how the spindles are physically arranged. Would you provide pictures of these? I've never seen a big multi-spindle arrangement like this up close but I'd love to given the opportunity.

154

Show"N"Tell ( Your Machines) / Re: 5 axis Spinning Lathe: machine and control panel in progress

« on: March 04, 2010, 04:43:17 AM »

This is the way some of the big Leifeld lathes do it, other "playback" lathes use encoders on the cross slide and record a route as the roller is moved across the face of the tool. The "gap" can then be set for a basic material thickness and edited to allow for thinning or compression.

I think Mach3 has a tracking facility but I've never used it. Suggestions from the audience?

155

General Mach Discussion / Re: RoHS and CE Compliance

« on: February 08, 2010, 07:33:55 PM »

The CE mark is a fairly general quality/safety mark for almost anything sold within the European economic area, and RoHS is now firmly in force for all but the military. So basically anything you buy new in Europe will almost certainly be compliant by now. Is this an end user requirement? It's not a hard one to meet.

156

Show"N"Tell ( What you have made with your CNC machine.) / Re: MODEL 629 S&W MAGNUM

« on: February 04, 2010, 04:12:40 AM »

Wonderful project! I used to have a model 29 classic hunter, 8" full lug barrel and unfluted cylinder, delicious fun and a great way to turn railway sleepers into firewood.

Ideas for the barrel: Use a section of .177 airgun barrel? Or use a bit of it for a guide to gradually scrape out grooves? A spring loaded cutter at the tip of the rifling tool would be easy enough to make, and would just wear a groove gradually. File the rifling out very carefully at the crown of the barrel to make it look deeper, if you need it, and if you can find a file that small

157

Show"N"Tell ( Your Machines) / Re: CNC Welding...

« on: February 04, 2010, 03:58:42 AM »

the big rectangular flanges I put in my show-and-tell page were for another accelerator not superconducing though.

158

Show"N"Tell ( Your Machines) / Re: 5 axis Spinning Lathe: machine and control panel in progress

« on: February 04, 2010, 03:20:13 AM »

^^ Yeah, that's the other way to do it

I've come to the conclusion with my two spinners - Who have clocked up around 40 years experience between them - that it's not quite as simple as it looks, never quite obvious in its mechanism, and flexible enough that it is either surprisingly adaptable when required or utterly treacherous. I think they may be Jedi on the quiet.

incidentally I've just worked out that the contact speed of the edge of a big dish blank, when it is trimmed off with a lathe tool, is over 4,200 surface feet per minute, so it's hardly surprising the swarf flies about like it does.

159

Show"N"Tell ( Your Machines) / Re: 5 axis Spinning Lathe: machine and control panel in progress

« on: February 03, 2010, 02:45:43 PM »

My best guess would be to spring load the tool or use a load cell or other indicator.

Large CNC spinning lathes use hydraulic rams with (I think) linear encoders. very expensive, especially if someone plays with it and drives the ram into a rotating tool that weighs as much as a fully loaded pickup truck. It has happened.

160

Show"N"Tell ( Your Machines) / Re: wiring guide fun

« on: February 03, 2010, 02:29:59 PM »

I have plenty of lead solder

OpenOffice is very good for doing layouts, all the way up to fairly decent technical drawings.