RE: CNC versus Rapid Tooling from RP

Date: Thu Feb 18 1999 - 17:45:56 EET

Dear Steven and other RP-friends,

In our opinion (Experience: 30 years of toolmaking , 6 years in the area of
Rapid Prototyping (FDM, Kira-PLT, LOM, MJM, Vacuum Casting, High Speed
Milling, 5-axis milling, lasermilling and EDM) and available
farmers-knowledge) it is very difficult, if not impossible, to make a
comparison between CNC and RP derived RT routes. The reason why?

Everytime you make a mould you try to find the best suitable (manufacturing)
technology. In most cases it is clear that a certain mould can be
manufactured in the best way by only milling or EDM or only Lasermilling or
only SLS or an indirect technology like ECO-Tool or Keltool (or a
combination of these technologies).

When you have for instance a depth of a cavety of more than 15 mm (with
enough width) then Lasermilling is out of the picture. When you need sharp
(no radius allowed) internal corners in your cavety then milling will become
difficult. You always need EDM afterwards. The choise also depends of the
quality of the mould and the products to be produced in it........And so on,
and so on. A comparison is therefore difficult to make because a comparison
is only usefull when you compare the same things (sounds logical to me). So
a comparison of the same geometry made with different technologies is the
only good one. But this is not fair because you will never make a deep-draw
tool for sheetmetal forming a 1000mm * 1000mm sheet with SLS. Which does not
imply that SLS is a bad tooling proces. (for me as a milling-freak it is,
but that is of the record)

But....... last month we made a mould for one of our customers and in that
case it was difficult to decide to use which technology. To help our
customer in the most reliable way (there was something at stake for them) we
chose High Speed Milling on STL-files of the core and cavety. But we think
that lasermilling, ECO-Tool and also SLS could be suitable. Therefor we
decided ourselves to also make the core and cavety by lasermilling and
ECO-Tool to make a comparisson. We will do this when we have the time for it
and hope to present the results at the coming TCT'99 event if the comittee
accepts our paper on this subject. Also incooperated in the paper will be
the use of STL-Technology and -files in the whole process from conceptual
design until the making of the (injection moulding) tools.

So a long story from Holland with not a straight answer but hopefully
something is clear from our opinion and will become clear in October when
the comittee of TCT'99 accepts our paper !

All the best from Holland

Jan Willem

Ir. Jan Willem Gunnink
TNO Industrie
Division of Production development
Department of Industrial Prototyping
P.O. Box 5073
2600 GB Delft
Tel: +31-15-2608747
Fax: +31-15-2608725

> -----Oorspronkelijk bericht-----
> Van:
> []
> Verzonden: donderdag 18 februari 1999 10:32
> Aan:
> Onderwerp: CNC versus Rapid Tooling from RP
> Does anyone have any references which compare CNC (high speed or
> otherwise) against RP derived Rapid Tooling routes?
> As CNC is getting faster and faster, both in terms of spindle speed,
> computer processing speed and job throughput, can anyone see a life for
> Rapid Tooling from RP beyond the next 5 years (or less?) except for
> certain niche applications?
> I would be interested to hear of any views, particularly those from the
> industrial readers of the list who are changing, or who have changed,
> from Rapid Tooling to CNC.
> I know the list has discussed this topic before (though not recently)
> but in a constantly changing environment it pays to keep up with
> developments in the older, more traditional tooling routes.
> Steve Windsor
> Rapid Prototyping & Tooling
> Rover Group
> University of Warwick
> Coventry, UK
> Tel + 44 1203 524907
> Fax +44 1203 524878
> email << Bestand: ATT04697.ATT >>

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