Wireframe Toolpaths.

[George Hardwick]

Before we start please forgive my ignorance and stupidity.....

But If I construct a wireframe with a profile at each end and 2 inbetween. Then do a loft toolpath to cut in the across direction, with along and across cut set to 1.5mm and cutting direction across. Why does the across cut spacing alter and get finer as it progresses along and past the inner profiles? If this makes sense to anybody can you help???

George.

[d00d]

Sounds like you need to do a ruled toolpath and break them down into 2 seperate operations, but I would really need to see the geometry 1st. Can you post to the FTP site?

[Glenn Stephens. from CCCS]

It's how ruled toolpaths are calculated. The max stepover you give it is applied to the LONGEST chain you select. All other chains are broken up into the same number of cuts.

 

Example:

 

You have 3 chains. 1 is 50 mm, 1 is 40mm, and 1 is 70mm.

Your stepover is 3.5mm

70/3.5=20 steps

The respective spacings at the chain positions are then:

50mm/20cuts=2.5mm/cut

40mm/20cuts=2mm/cut

70mm/20cuts=3.5mm/cut

[George Hardwick]

Thanks Glen I see what your saying that is what is happening.

If I break it down I no longer get a blend between contours??

 

Thanks George.

[Glenn Stephens. from CCCS]

I assume you have mill level 1 right?

The only way to get a constant step for all passes along the entire path would be a surface flowline toolpath (mill level 3) on the ruled surface you create from the same geometry. You end up with quite a few incomplete passes because of the different "widths" at different parts of the surface.

If you create the surface, offset it up by the radius of your tool (ball E/M), then create-curve-flowline on it with whatever spacing you'd like, You'll get 3d curves you can chain with no comp and at the center instead of the tip to essentially get the same toolpath.

 

OOOOLD school

[Scott Bond]

quote:

---

OOOOLD school

---

I still use old school for some stuff, but only cause I'm old guy. If I was a new guy just starting out now, I wouldn't bother learning the older labor intensive stuff.

[gcode]

quote:

---

If I was a new guy just starting out now, I wouldn't bother learning the older labor intensive stuff.

---

Scott, I'll bet some of the "kids" don't even know

where to find the wireframe toolpaths

 

Hey Glen,

We don't see you much around here. Stop by more often

[SVO]

Ok I admit it. I use wireframe toolpaths all the time. I use level 3 but still find myself returning to the tried and true. For me they are quick and easy, and provide great results for most work. They've been in the menu for a long time and I hope they never go away.

 

Dan

[Fig sign]

quote:

---

--------------------------------------------------------------------------------

Ok I admit it. I use wireframe toolpaths all the time. I use level 3 but still find myself returning to the tried and true. For me they are quick and easy, and provide great results for most work. They've been in the menu for a long time and I hope they never go away.

---

+1000

 

I use them mostly to bypass the negative surface offset limitation (tool corner radius less then surface offset value )

Wirepathes have no such limitation.

I only want to add that mostly I use curve2d

toolpath and many times you can use it istead of others .

It is easier and simple .

 

Iskander teh oldtimer

[George Hardwick]

Glen.

Level 2 + Solids.

Its not for a specific job its just I like to try and undrestand what you can and cant do and why.

How come you know all this stuff and i'm just stupid....

[Guest CNC Apps Guy 1]

How come you know all this stuff ...

 

Glenn's been around programming for a looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong time. And the dude is definitely in the top 2 for smartest people I know. Besides, he's got a BA in Mathematics I believe, He just "sees" that kind of stuff.

[gcode]

quote:

---

He just "sees" that kind of stuff.

---

He once solved a post problem I was

having, on a cell phone while sitting in a traffic jam. I was looking at the stuff on my screen and he still was about 5 pages ahead of me

[George Hardwick]

I am in complete awe, of Glenn's knowledge and intellegence.

But are you trying to say that in order to understand Mastercam you require a Degree in Mathmatics?

[Guest CNC Apps Guy 1]

No, I'm not saying that at all. The 5-Axis Post stuff now... that's another story. It does not require a degree in Mathematics but I'll tell you what... it SURE does not hurt in the least bit. You do need a good grasp on vector math though, other wise you'll be in deeper than you can imagine.

[Scott Bond]

Hi George

I am saying the opp.

quote:

---

I still use old school for some stuff, but only cause I'm old guy. If I was a new guy just starting out now, I wouldn't bother learning the older labor intensive stuff.

---

The new stuff does all the labor intensive stuff for you,,you are better off investing your time in the new stuff. A new guy needs to learn what he needs to be competitive today, he does not need to learn anything from the last version.

[Keithm]

Some times the old school and the basic stuff turns out to be best.

[George Hardwick]

Whatever the advise, I am keen to learn and want to learn, if only for the hell of it.

But. For example ( Max stepover is applied to longest chain,all the other chains are broken into same number of cuts.) I got 6 diff Mastercam books here, could not find that imformation anywhere.Without hounding the hell out of you poor long suffering folk how can I get the answers.

LOL.George.

[Guest CNC Apps Guy 1]

Yeah, sometimes I reach in that old bag too. Not too often though. I'd rather learn the new stuff, then if I find a limitation revert to the "Old School". George, some of us have been using MC since Version 3 - like me (some even before that like Scott, Glenn and others). When you have that much history with a product... you tend to know things the "average" (whatever that is) guy doesn't. Mastercam's been great in that it allows you build on what you know from past experience with the product.

[Guest CNC Apps Guy 1]

quote:

---

...I got 6 diff Mastercam books here, could not find that imformation anywhere....

---

You'll not find that in any books... but Mastercam being the superior product it is gives you that info in (where of all places) help. Imagine that...

 

Stolen from Help Below...

quote:

---

...For loft toolpaths, the along cut distance sets the cutting increment in the along direction, applied to the longest along contour. This parameter also determines the smoothness of the surface. The across cut distance sets the cutting increment in the across direction (perpendicular to the along direction), applied to the longest across contour. The system uses this distance to calculate the cutter stepover between each along cut.

The more drastic the curvature on the part, the finer the cut distance should be. On a fairly flat surface, a larger cutting cut distance may be used (for example, 0.150).

 

Note: A smaller cutting increment creates a smoother part. Also, a smaller cutting increment creates a longer final NC program that can take longer for Mastercam to generate.

The following graphic shows an example of along and across cut distances for a loft toolpath.

---

[Philcott]

George,

 

You may be asking the question,

quote:

---

Without hounding the hell out of you poor long suffering folk how can I get the answers.

---

but we all learn from the answer.

 

Phil

[George Hardwick]

Sorry James.

Should have gone there first....

I'll limp any and lick my wonds..

[George Hardwick]

Limp away ( cant even type now)

George.

[Noel]

You can lick your own wond.

 

 

Were not worthy

 

 

Noel

[Guest CNC Apps Guy 1]

ROFL!!!!!!

 

Mastercam's help though is one of the best help systems for any software I've ever used. It would be nice if they couls make it so you can ask it questions in X. I like that about Microsoft.

 

JM2C

[George Hardwick]

HE HE..

I have put in some extra chains in order to even up the distance leaving the chains more or less the same lenght. Now I have an even cut spacing along the component.

Anything wrong with this?

George.