Re: CAD / CAM 1 (was Re: STL settings in Rhino for MM2 output.)

From: Paul Suomala (psuomala@sandersdesign.com)
Date: Fri Sep 29 2000 - 21:21:33 EEST


Gentlemen,
 I use Rhino on in intermittent basis, Sanders products every day.
 Presumably, the problem manifests itself as excess supporting wax being
deposited in places where it is not wanted. This will cause the part to
delaminate, or pit at the time of support material removal.
 The cause is possibly a "leaky" input file. Remember, the Sanders
machine can produce parts in slices as thin as .0005". If there are
leaks in the STL file, the pre-processing software (ModelWorks) will
find them. The first thing to do after completeing pre-processing of the
STL file is view the file in "BView" which enables each "slice" to be
previewed. When it is obvious, the part will not produce properly, time
to track down the STL file.
 Also, I am aware that Rhino has in the past (for me) had some
difficulty completing boolean operations concerning tall thin
extrusions. Watch the messages. Sometimes a small gap may develop due to
mathematical rounding errors which in turn gives ModelWorks fits trying
to figure out what is "inside" vs "ouside".
 The STL files usually are good provided the input file is
"water-tight". The only item of concern being the fineness of the
triangulation - coarse setings make circles into octagons.
 One of the recommendations I have made in similar cases is to explain
there is a problem, then direct people toward on of the freebie STL
viewing programs available on via the "Web" that has cross-sectioning
capability as well as error reporting (materialise.com has one). By
using the design software and checking in the 3rd party software, one
can usually home in on the problem.
 I emphasize that the best way to have a good STL file is to make it.
Repair is possible (once again Materialise and several others) in many
cases but most of the CAD packages of today make fine STL files of
proper models.

Happy modelling,
Paul Suomala
Sanders Design Intl

Stanley Lechtzin wrote:

> At 10:25 PM 9/28/00 -0400, you wrote:
>
>> Listers:
>> Any one out there using Rhino to design parts for Sanders MM2
>> output?
>> I not fluent in Rhino. But, I have two customers who are trying to
>> have us
>> build their very first RP parts using Rhino They are also "newbie"
>> Rhino
>> users. Problem is, the STL files are shot full of errors and won't
>> build
>> properly.
>> Anyone have some suggestions on how to get these people points in
>> the right
>> direction?
>> Paul Burr
>> B&D Sales Corp.
>> Cranston, RI
>> 401-781-4810
>>
>>
>> For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
>
> Hello Paul -
>
> We offer an online Rhino for jewelers. See below:
>
>
> =
> ======================================================================================
>
>
>
> Introduction to CAD/CAM I
>
> This online course is based on the use of Rhinocerous® 3-D NURBS
> modeling software for the Windows operating system. It is directed to
> jewelers, product designers and sculptors who wish to create solids
> models and tangible objects via STL file export to rapid prototyping
> systems.
>
> Students will need access to a Rhino workstation which consists of:
>
> * A Pentium II, 300MHz (or faster) PC computer running the Windows
> 98 (or newer) operating system.
> * A video display capable of a minimum 1024 x 768 x 32bit color.
> * Rhino Version 1.1 or higher
> * An Internet connection and an email account.
>
> Matriculated Tyler School of Art students who register for this course
> and pay their lab fee will have access to all of the course
> requirements, both hardware and software, in our PC CAD Lab (Tyler
> room 102)
>
>
>
> Course Objectives
>
> You will learn how to:
>
> * Customize your modeling environment.
> * Create basic graphic objects-lines, circles, arcs, curves,
> solids, and surfaces.
> * Draw with precision using coordinate input and object snaps.
> * Modify objects with edit commands.
> * Display any portion of the model.
> * Import and merge models.
> * Output models to different file formats.
> * Create, test and verify solid models in STL file format for
> production of rapid prototypes.
> * Render models.
>
>
> -----------------------------------------------------------------------
> Note: A password is required to access all of the course lessons and
> exercises.
>
> Students who register for this course will be assigned a password when
> they contact Prof. Stanley Lechtzin via email at: stanley@home.com.
> Just click these links as you do not need a password to see the Home
> Page, Course Syllabus, Course Contents and a sample exercise; .
> -----------------------------------------------------------------------
>
> To register for this class, go to: The Temple University Online
> Learning Program
>
>
> -----------------------------------------------------------------------
> Prof. Stanley Lechtzin
> Temple University
> Tyler School of Art
> Metals/Jewelry/CAD-CAM
> 7725 Penrose Ave.
> Elkins Park, PA 19027
> phone: 215-782-2863
> fax: 215-635-2861
> email: stanley@home.com
> M/J/C-C web site:
> http://blue.temple.edu/~crafts/
> ACMET-Listserv:
> http://listserv.temple.edu/archives/acmet-l.html
> -----------------------------------------------------------------------
>

For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/



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