Help Getting Model From Rhino Or Lightwave To Shopbot

[courtney2018]

Hi all,
I'm about to buy a Shopbot and I have a question that I'm hoping someone can answer or has experience with.

Reading Shopbot's material I see that Partwizard can take a 3D modeling file from 3DSMax, Lightwave and whatever Rhino's filing format is. I'll be using Lightwave. I see that Partwizard can accept .lwo files, which is Lightwave's file format.

My question is this: how accurate is the conversion/translation from the modeling package to the final cut version off the Shopbot? Rhino should be no different than Lightwave.

I'm an aero-mechanical engineer, dealing mainly with aerodynamics and have modeled, meshed and analyzed lots of models. I'm used to a step or iges format out of the modeler and it gets converted in the mesher when the model is imported in. There's usually something that doesn't get translated just perfect. So that's what I'm trying to get the answer to really. When you go from a modeling package to Partwizard, are there any translation problems that would effect the accuracy? What do you do to solve those issues?

I'll be using the Shopbot for making guitars mostly.

Thanks in advance!

[khalid]

Okay.. Just tell me in which format you will export and how much tolerance value you will keep in exporting... I think CAD model will be imprted in any CAM without distortions or translations.. Its the tooling and mechanical/electrical capabilities of your controller+ machine to get the accuracy...

If you have very high end machine with linear rails and ball screw and high repeatability, well aligned machine and your controller can micro step and your tool has no run out and you put no mechanical error (human error).. and the material you used is not anisotrophic you will get exactly the same thing you modelled in CAD...

My machine (Home MAde MDF) is not an high end machine like shopbot, but i am getting accuracy and repeatability within 0.1 mm... that can be further improved if i have a good tooling, levelled, well align.... just compare the following CAD model and out put from my machine.. see the details where 3mm tool can get in..if i use 1.5mm i will get further resolution but with the cost of time...

Now tell me what can you get from Shopbot when you see my crude shaped machine... Offcourse very high details from shopbot... absolute results...

[khalid]

just compare the following CAD model and out put from my machine.. see the details where 3mm tool can get in..if i use 1.5mm i will get further resolution but with the cost of time...


44076.jpg


44077.jpg

[courtney2018]

Thanks Khalid!

Since Partwizard will accept a .lwo file then I won't be exporting out of Lightwave. I'll just save my model as a Lightwave object (.lwo) and bring that into Partwizard.

But Partwizard should have to convert that file into another file for toolpath creation. There's a translation there. I was concerned that there might be some issues (maybe rare on occasion) with that translation. When you go through a translation there are always errors (like round-off errors). Those errors might not be visible to the eye when you cut the part, but there are errors. Just wanted to know if anyone noticed those errors being large enough to see by naked eye and what was done to fix those errors.

Are you using Rhino or Lightwave or something else? What steps do you take from modeling package to actual cutting of the part?

Thanks!

[shoeshine]

Hi Courtney,

I use Rhino to build my models and though mostly I do decorative work, I have achieved tolerences of .015 or so when I mic a piece. So no, nothing visible to the eye.

Rhino exports a dxf up to .001 tolerence that partworks handles as is, so the errors are more likely in the actual tooling than in the software process.

Caveat being that the machine has to be calibrated properly and one has to actually mic one's bits (I dont own a 1/2" bit that is actually .500)

Chris

[courtney2018]

Thanks Chris.

I don't have a model of anything right now, but would you mind me sending you a lightwave file sometime and just see how the translation goes?

[shoeshine]

sure thing

chri(at)schaie(dot)com