Re: Flexible materials for scuba fin

From: Nick Osborn (Nick@swiftech.co.uk)
Date: Tue Nov 09 1999 - 09:17:05 EET


Marshall

Just over two years ago we did a project with an automotive sealing system supplier (large tier 1) which included running EPDM (tyre rubber / scuba fin material to you and me) in very thin sheet form through our LOM 1015 machine. We successfully proved the principle and built a number of quite complex corner seal components in laminated EPDM, using liquid EPDM as the bonding agent, thereby yielding a part that was made of 100% production material.

Only drawbacks = stepped surface finish (difficult to hand finish to cosmetically acceptable levels) and non-moulded performance characteristics. This reinforced our belief that for now (i.e. next 5 years or so) its better to give people what they want (i.e. real parts real quick, moulded from a rapid tool) rather than what we think they want (i.e. right material, "non-representative of production" process). I figure within 5 years RP will have enough of an effect to seriously change the production processes themselves, which of course changes the argument somewhat.

The tier 1 patented the process but I don't believe they are using it.

Best regards

Nick

Nick Osborn
Managing Director
------------------------------------------------
Swift Technologies Ltd.
140 - 144 Station Road, March,
Cambs. PE15 8NH, UK

"Real Parts Real Quick - Because Time Is Money"

Tel: +44 (0) 1354 650 789
Fax: +44 (0) 1354 650 799
www.swiftech.co.uk
-------------------------------------------

>>> "Marshall Burns" <Marshall@Ennex.com> 08/11/99 15:02:47 >>>
Hi folks,

    First question: Does anyone know the technical numbers that describe the
material properties required of a SCUBA FIN? Properties such as modulus,
elongation, tensile and flexural strength, etc. and also surface smoothness?
Primarily, I see a need for a material that combines being SOFT and
TOUGH, but I'd like to be able to express that quantitatively if I can.

    Second question: How close are we to being able to deliver those
properties straight out of a fabber today? Many of you are experienced in
using flexible materials on today's fabbers (SLA, Sinterstation, maybe some
on LOM). How close could you come to making a scuba fin that you could put
on your foot and go diving in?

    I'm not talking about a secondary process that casts in a different
material after fabbing a mold or master on the fabber. I'm talking only
about materials that come directly out of the machine.

    (This posting carries on with the discussion last week about direct
manufacturing of products in fabbers. I've told you that I'm writing about
this for an upcoming issue of the RP Report. You may have seen a TV
commercial by UPS that shows a scuba fin being delivered from an Internet
vendor by a fabber in the customer's home. I'll be writing about how far
that fantasy is from becoming reality. Thanks for your help with my research
on it.)

Best regards,
Marshall Burns
President, Ennex Corporation

Marshall@Ennex.com
Los Angeles, USA, (310) 824-8700
www.Ennex.com

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

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



This archive was generated by hypermail 2.1.2 : Tue Jun 05 2001 - 22:53:22 EEST