Drawing Question

[jspangler]

Hi

Since I have NO experience with autocad, etc. and am self taught on MC8, I was wondering if anyone culd recommend any books on drafting? My problem is getting the drawing from the part into the computer accurately, and takes a ton of my time.

Anyone have any tips on reverse engineering parts??

 

Thanks

 

Jspangler

[Tony]

You can't Just import the Model?

[jenks]

Edward G. Hoffman has a book called "JIG AND FIXTURE DESIGN". In the book he covers some drafting and tolerancing.

 

"MACHINERYS HANDBOOK" also has a drafting standards section.

 

Try "MODERN MACHINE SHOP" online at WWW.MMSONLINE.com. They have some good reference materials, and links to many other web resources.

 

As for reverse engineering, I have an old Tree Journeyman 325 that sits idle quite a bit of the time, and I will put my parts in it, use an edge finder, dial indicators, micrometers etc., and get a basic layout of the part I am trying to duplicate. I will then draw the part in MCAM V9 and dimension it. I compare the part to known standards and move geometry around till I get a part that satisfys the requirements. It is helpful to dimension with the globals set for dimension regeneration. It is a great way of auditing your work.

 

It is a pretty crude method, but it gets the job done.

[Brendan P]

If you really want to cheat and save time,then

you may want to check out this site.

http://www.trixsystems.com/tractrixcam.html

 

You "scan" your cad(raster)drawing(supplied by your customer).

It then converts it to a (vector)drawing,which

will allow you to import it into Mcam and start

giving your toolpath.

Although I have never used it, and cannot comment

on if it is good or not,you may want to check it out.

As far as books,there are many to choose from.

If you are using AutoCad,there is a thick book

called "Harnessing AutoCAd" which I would highly

reccomend.

[cadcam]

Bucket Head Did you know that mastercam can do Raster to Vector?

 

I have done this many of times.

this part of the engraving package or you can just purchase the Raster to Vector without the engraving.

[jspangler]

HI

Well since I am building my own parts ( headers and turbo kits for Imports), I usually start with the factory exhaust manifold gasket, and go from there, but some times the bolt holes, or ports aren't in a symetricla layout ( as far as I can tell ), and it takes forever to get the drawing right.

Any idea how much the mastercam raster 2 vector software is going for, and is there a demo available?

 

Thanks

 

John

[jspangler]

SYMETRICAL,

sorry haven't finished my coffee yet

 

John

[David S]

Always remember where your origin is when you doing design. Like doing MasterCam programming, plan your origin point before you starting your job.

 

There is a little deference between Cad origin and Cam origin. Cam origin is holding, cutting and clamping oriented while Cad origin is purely for measuring and developing design.

 

[ 02-18-2003, 12:17 PM: Message edited by: David S ]

[Brendan P]

No CadCam I didn't.

This is what I like about this forum soo much.

Never ending Mcam info.

We do not do engraving so I dont think we have

it if it is an option.

I feel more comfortable drawing the parts

myself,so I don't know if I would even use it.

[rchoward]

i agree remembering your origin is very important

 

for u 2d is probably good enough so don't worry about solids and surfaces for most parts

 

i find the offset steps, trim, and fillet commands to be most useful

 

you can trim to a sharp corner by setting your fillet radius value to zero

 

cad work can fly, look for patterns, try new things, look at all the sofwares options and try them out and you will get fast... oh yeah draw lots... and lots and lots then you will get really fast

[PE @ IHS]

Raster to Vector is fine for artwork, engraving, etc. but I would NOT use it for scanned CAD Data. The smallest wrinkle in the paper, a smudge, a drop of coffee, or even slight variance in line thickness will throw your tolerances out the window. JPEG, GIF etc. are a series of dots that are an approximation of the actual part.

 

Raster to Vector is an approximation, nothing more. Rast2Vec will bring in hundreds of small line and arc segments. You can filter them, but the more you filter, the worse your accuracy.

 

Please correct me if I am wrong.

 

Peter Eigler