This check box is in Toolpaths, Job setup. I presume it should compensate feedrates around arcs. I tried it once before without success. I just had another go and couldn't get any sense out of it. When the toolpath in on the inside of the arc, the feed rate should slow. When on the outside, it should speed up. The amount of compensation is easily calculated from the ratio of cutter radius to job arc radius. What I get from checking the box is somewhat random, arbitrary, extraordinary, surprising, illogical feed rates. Has anyone managed to get it to work or found another way of achieving the same thing? Thanks, Hugh.

Thanks BerTau. How embarassingly obvious. Not hard to tell I'm only half computer literate, is it? Hugh.

Thanks Glenn. I presumed the error message was offering me the possibility of open pocket within the facing operation. From your comment I get the feeling this is not available. I did end up using contour. Hugh.

After reading a topic, clicking the "Go" button always returns to the top of the list of topics page, even if the last topic selected was towards the bottom of that page. Is there any way that it can return to the list of topics as displayed when the topic was selected? Thanks, Hugh.

Thanks Andrew. When I tried to use a single line the resulting error message offered me the option of an open pocket. Jack, I think if the width of the area to be faced is less than a system defined fraction of the cutter diameter, the result will be a single pass. Hugh.

Thanks Jack. I couldn't get facing to work from a single line as I tried to say above. Have I missed something? Hugh.

Thanks Kevin. I didn't want to waste time creating unnecessary geometry. Looks like contour might often be more useful as it can follow a single line. Hugh.

What geometry can be used for facing? I find I often don't want to face the entire top of the stock. Right now I want to just face a strip on one end. If the cutter centre line would follow the end stock boundary that would do, but It doesn't like it. The error message says "Warning, not all boundaries are closed. Select open pockets or close chains." I guess I could offset the stock boundary and use contour. At which point I would ask how much can facing do? Thanks, Hugh. [ 08-20-2002, 05:02 AM: Message edited by: Hugh.Venables ]

I don't have any way of knowing that John. I'm not in touch with enough toolrooms. You would think with it being taught at Moorabbin for 10 or so years there ought to be quite a few but I don't know of any other regular Melbourne contributors on this forum. Hugh.

G'day John_o mate. Moorabbin campus of Homesglen TAFE (previously of Chisolm TAFE, previously Moorabbin TAFE, etc.) has been running Mastercam classes for close to 10 years, but I guess you're not going to like driving 8 hours or so each way. This forum is the place to solve your problems. These guys are fantastic. Hugh.

Jay, Rick is just saying the toolpath will be different for tip or centre compensation. I don't think he means to imply that the machined part will be different. Rick, what is that Big Book? Thanks again guys, Hugh Venables. [ 08-05-2002, 07:31 PM: Message edited by: Hugh.Venables ]

Gentlemen, thank you all for your input. I'm not just relieved, I'm better informed as well. Hugh Venables.

Thanks Finecut, that's a very useful resource. Hugh Venables.

Thanks James. Thanks Jay. I guess what I'm most concerned to find out is whether the part will be produced accurately using either method. Rick's reply suggests a possibility that it may not. James, your reply suggests that too. What differences am I looking for in backplot? Hugh Venables

What differences exist between these two? More importantly, what sort of factors should be considered when deciding which to use? Thanks, Hugh Venables.

Finecut, thanks very much for that. I've been trying to find out how to do that for years. Got a new problem, though. Got to figure out how to remember it............ Rick, please tell me more. Can you expand on the sort of difference it will make. I used "tip" without thinking as it's the default. The part looks good but is difficult to check. Might be able to look at the end of it in the profile projector using surface lighting. Can't find anything in help that explains tip comp any further. Just had a look through the V8 Applications guide. Couldn't find any information or any example where "center" was used. Hugh Venables

Hi Cowboy. I can't help you with these but have a look at some of the recent discussions on this forum about Mazaks. It seems not all Mazaks have the optional ability to read ISO code and will only operate on Mazatrol, particularly lathes. If that is your case, the Camaix MCAM posts that output Mazatrol could be worth a look. The post we use to output ISO to our M2 is a modified generic Fanuc that a good friend wrote. Hugh Venables.

Thanks James. I'm machining a small aerofoil (25 m.m. x 3 m.m. x 200 m.m. long) with a 20 m.m. ballnose tool. Around the front it machines around 90 degrees, (How do you get a degree symbol from a keyboard?) at least it does when I write the last few lines down to the centre line. It doesn't seem to matter whether tip comp is tip or centre. Maybe it only affects the tool touch off, as you said. Thanks, Hugh Venables.

On the surface parameters page it is possible to toggle between tip and centre for tip comp. It doesn't seem to make any difference. Surely it should to, say, a ball nosed cutter? Thanks, Hugh.

In the European system, module equals pitch diameter in millimetres divided by no of teeth. There is an English module system, based on the inch system. Module is a dimension and therefore more useful than diametral pitch which is a ratio, but then the whole metric system is generally more useful the the imperial system. Hugh Venables.

Thanks for your time guys. Plastav, I presume you mean Surface, Finish, Contour. This does result in down cutting. The tool path Down cuts alternatively either side of the highest part of the aerofoil section. Unfortunately, it never cuts the highest part of the section, leaving a significant ridge uncut. I can't see how to solve this. What logic would lead you to select a contour toolpath for this job? BerTau, that does give some control except that setting different maximum stepovers causes moves the start point from one corner to another, but of course I have another problem. As the toolpath is rising up the section it is down cutting but as it drops down the other side it is up cutting. To solve this I think I would need to break the surface at the highest point and have two operations. Trevor, maybe it's about time I upgraded to V9. There is also another problem I didn't mention before. The front of the aerofoil is at Z0. I'm using a 20 m.m. ballnose cutter. Logic tells me that if a cut is made along the front at Z-10 or lower, there's a nice finish reference on the front of the part. Maybe logic doesn't cut it any more as the cutter never gets down to Z-10. Hugh. [ 07-23-2002, 08:30 PM: Message edited by: Hugh.Venables ]

I need to cut a symmetrical, constant section aerofoil. I plan to do this with a ball nose one face at a time with extra stock at the ends of the section to clamp. I can't see how to control the machining direction when cutting one way. If I change the machining angle from 0 to 180 it does machine from the opposite end but starts at the diagonally opposite corner so it's still up cutting. Is it something to do with how the surface was created? I'm using V8.1.1 Thanks, Hugh. [ 07-23-2002, 12:34 AM: Message edited by: Hugh.Venables ]

Peter, that's very interesting. I have been wondering about this for a while. Do you recommend it? Found any limitations? Is it your favorite Mazak post? What Mazak control(s) does it output to? How do the programs differ from those generated at the control? Can you use it to transfer control generated programs to the PC for storage? Are the Mazatrol programs much smaller than an equivalent ISO program? Thanks Hugh.

Reminds me of the story about the adoring mother watching her child in a march past. They were all out of step except her child. It's a bit hard to argue with a poll. Hugh Venables.

Duckman, I suspect you haven't explained your problem in enough detail. What do you mean by "when writing to an NCI file"? What C-hook are you using and for what purpose. As Jamman said, for contouring and pocketing, there is selection of computer and/or control compensation at the top right corner of the second parameters page from the operations manager. Surely it's not this simple? Hugh Venables.