Messages

191

General Mach Discussion / Re: Odd Startup Behavior

« on: December 12, 2007, 07:17:28 AM »

I've had a similar problem that I traced to electrical noise.
Mine was also a bit more random, the Z axis would work fine then suddenly it would go up instead of down but the DRO was showing it going down. I had fun with that one for a while till I figured it out 

Your obviously getting somewere as you can repeat it consistently which is the best start.
Perhaps you should strip down to the basics with only the axis being controlled by the LPT and then work back up from there adding the home switches then relays etc until you find the root problem.

Steve

192

General Mach Discussion / Re: Continuation after tool change

« on: December 10, 2007, 03:16:16 PM »

The problem with a macro is that the position that you use to zero the tool at will be different for each job.
It's very convenient to just move the tool over on the jog buttons, change the tool and then move over to a bit of the job that's still at zero. Zero the z axis, jog it up a little then press the start button to continue.

By the way I us an ER collet chuck so I can't really use a set tool height with each tool and use tool offsets (I don't know how to anyway  )

I've not yet had time to check if my mill still does this but it def used to.

Kind of agree with you Stirling.

Steve

193

General Mach Discussion / Re: Continuation after tool change

« on: December 07, 2007, 10:49:34 AM »

I normally used this as well.

I can't see how you'd do it any other way with manual tool changes, Like Stirling I've not done any multi tool jobs for a while, I'll check mine this weekend. If work doesn't get in the way AGAIN.

Steve

194

General Mach Discussion / Re: Running 4th axis independently from xyz

« on: October 17, 2007, 12:02:49 PM »

If I understand this correctly you need to be using the A axis, you'll need a driver for the stepper and set up the axis in Mach but this is the normal way.

Steve

195

General Mach Discussion / Re: Cutting a YZ arc: Where do I put the K?

« on: October 17, 2007, 11:58:36 AM »

Hi

I'm no expert but I'll give the answer as I see it.

The IJK is the centre point of the arc relative (normaly, but some are from the zero point) to the start position I is in the X axis, J in the Y axis and K in the Z axis.

So if your bar is length ways on the X axis you need to be using J and K to set the radius in the YZ axis, the J would be the centre of the bar stock and the K would depend on the start point of your arc.
From what your saying I'd guess that you've got the K too high making a large radius that is giving a flatter curve than required.
A quick easy way to work this out is to draw it in cad and measure the distance from the start of the curve to the centre point, most cad systems will also give the XY measurment, the Y (K in your Gcode) measurment is the one you need as I presume you know the X (J in your Gcode)

Just done it using your sizes. J=0.3078 & K=0.1060

If you have the bar along the Y axis you'd use I,K

Are you sure your wanting to do it this way as it'll take a lot of cuts to get a smooth finish along the length, but then a cutter of the diameter required would be huge for a home workshop.

Hope this helps
Steve

196

General Mach Discussion / Re: Cutting Camshafts

« on: October 14, 2007, 07:54:35 PM »

Hi

didn't get anything done on the radial this weekend, I did a bit of manual machining on a Stuart steam engine.
Times a little limited at the moment but I hope to get on again soon. A little drunk at the moment as well so hope it all makes sense

Steve

197

Mach3 under Vista / Re: Your opinion of Vista ?

« on: October 14, 2007, 07:04:40 AM »

I'll not be changing to Vista any time soon, not because I don't like MS OS's but because everyone I've talked to had said they have had problems and that it's not got anything that helps them get the jobs done any better than XP.
I liked 2000 better than XP but XP had quite a few items that were better/easier so I changed, it works and that's all I wanted it to do, I'm not interested in fancy graphics and twerly images etc, I want to do a job and I want to do it with the minimum of hastle.

Also to make an OS that doesn't work with peoples older equipment is plain stupid.

Steve

198

General Mach Discussion / Re: Cutting Camshafts

« on: October 13, 2007, 07:03:52 AM »

It depends on what cam software you have. I have meshcam for doing 3D work and this has a basic 4th axis setting so all you would do is make a 3D model in say Alibre Express and then export an STL file. You would then cut down to say half the depth of the blank and do it in four 90 degree sections, meshcam doesn't keep the 4th axis revolving it just steps it round the treats the job as a new surface profile to do stepover milling with a ball cutter, most likely long and tedious.

You may be able to get a program that can use a flat ended cutter and just revolve the 4th axis round while the Z goes up and down but I suspect this will be quite complicated to work out as the ramps on the cam lobe will not be cut by the centre of the cutter, it'll move to the side of the axis of rotation as the cam profile rotates, just the same as using a flat follower. You cutter would also need to be quite a bit bigger diameter than the cam profile, also the full cutter diameter will only be effective on the centre of the cut so you would end up with a scalloped cut on the ramps.

A better method is to hold the blank vertical in a chuck bolted to the table and use a special cutter that like a T slot cutter (effectively using a horizontal mill), you use a 21\2D CAM program then like lazycam to create the code from a normal cad drawing. Advantage with this method is you don't need the 4th axis

The real problem is creating the cam profile in the first place, you can use a spread sheet to drive the cad programs generation of the profile but I've never done this so I have to basicly draw points and use a spline to join them and create a smooth profile.

I'm in the process of making an Edwards radial 5 and the latter method is what I'm doing, I've got the profile and the blank done, I used sheetcam to create the gcode but I've not yet cut the cam, I may get it done this weekend, I'll take some pics if I do then you can see how I did it.

Steve

199

General Mach Discussion / Re: Upgrades, what a pain in...

« on: October 12, 2007, 07:17:03 PM »

Not had a problem yet upgrading, I do keep a copy of the mill.xml in case it gets trashed but that's about it.

If your unsure just change the views setting to detail, then click the type tab at the top, select all the .xml files and copy to another folder, then copy them back into the mach folder after installing the new version.

Steve

200

General Mach Discussion / Re: Post processor help

« on: October 12, 2007, 07:09:50 PM »

Mach handles tool changes no problem, just use M06 (normal gcode tool change)
Check in the general section top left, there is a few options for what the m06 does.

You can copy and paste the three sets of code together with an tool change before each set of code, you may have to get rid of line numbers though, not sure about that bit, but there are a few programs available that will help you with that.

The basics of gcode aren't hard so it's worth learning.

Hope this helps as I'm no expert :-)
Steve