Problems with negative angles...

[Gustavo Fonseca from ATL usinagem]

Our company use to machine automobilistic models. They are plenty of "negative" angles.

Mastercam theorically have the necessary resources to do it.

 

Machining a single rear side door model, that have, in its contour, negative angles,

Mastercam took eight hours to calculate the toolpath and the result was very, very poor

 

The resulting toolpath just machined two little "regions", and we could not use this toolpath.

 

We do know that hardware resources are important but we are sure that Mastercam have a lot to

improve in machining negative angles. Powermill, for instance, do the same work faster and better.

 

Because that, we are planning to replace our hardware. Today we are using a P4 2Ghz 512RAM HD 80GB,and we think it´s not too bad. Not that justifies so poor results.

 

 

Have anybody get results like that before?

[Donizeti Pinto]

I´m supposing you are using a dove, a slot or a lollypop tool, and the calculation in this case is really very very slow, I think.

 

As it is today, indeed, machining operations on negative angles takes much too time to be calculated.

 

I´m sure Mastercam must improve the calculation method to get faster results.

[Fig sign]

As I found in the past ,many users not really properly know how to work with undercuts milling .

Not to sound as a dumbass ,I was always successfull and did it a lot .

And helped to many others so I suppose from mistakes of others you used a lot of check boundaries and check surfaces were they must not be

If you make an undercut ,System still calculates from Tp CP top .

Show us example of your part and I may help .

[Watcher]

Agreed with Gustavo and Donizeti. When I was using MC a had the same problems: huge times to calculate the toolpath on undercuts using the tool types stated by Donizeti, and oftentimes I got poor results as well.

Frequently I had to use 2D wireframe toolpaths (when was possible) to work around this problem. When the last appmch9.dll for 9.1 SP2 was released, I read the entire documentation about it, and there, was stated that MC realizes shank gouge verifications and another checkings.

Well, I guess that a checkbox to disable this kind of verification would save a lot of time, and sometimes, the geometry is very simple and is possible to get good toolpaths without these checkings.

For instance, CNC software recommends that you disable the gouge checking in retract sometimes to get a proper toolpath. Well, I thinks that sometimes the same idea can be applied for shank verification and another checkings, because they are the reason of so high calculations time.

 

[ 04-06-2006, 12:29 PM: Message edited by: Watcher ]

[Gustavo Fonseca from ATL usinagem]

Dear Iskander Teh Owl,

 

Please apologize us about so many time without response. The work requiremetns sometimes get us far from our desires…

 

It´s a pleasure to hear from you that you was always successful with undercut milling. However, maybe we really need share you knowledge about it, and your help, indeed.

 

We prepared a simple model we named Contra.MCX (we put it in FTP) with some undercut milling. Working (in milimiters, sorry) with it and creating a Finishing Contour Surface operation

 

Whe used a disc mill, 100 milimiters diameter and 6 milimiters width, 3 mm radius corner. Tolerance of 0.025 and stepdown of 1 mm.

 

here in my computer Mastercam took near from 1 minute

 

A friend of mine have a Powermill seat. The same geometry, the same parameters took less than 1 second.

 

It´s just an example, in my opinion, about how much Mastercam must improve their undercut cutting comparing with their competitors.