Re: Growth over time

From: ross (ross@mnl.co.uk)
Date: Mon Sep 28 1998 - 19:18:47 EEST


Many thanks to all of you who replied either personally or to the group as a whole.

The one and only point mentioned consistently was humidity.

I have always been aware of keeping SL masters in a humidity-controlled environment. I was not aware however of the extent of the problems that would arise if I didn’t stick to these rules. Complying with the rules is what we have done with all of the models we have produced ever since our machine was installed over two years ago. A very high percentage of these models are used as masters for downstream processes and as a result are "trashed" once they have served this purpose. The actual lifetime of many of these models is usually only a few days. Due to this short timeframe, expansion from humidity has not caused us any problems. Until now ! Although we despatch our models with carefully worded handling instructions positioned inside the sealed packaging alongside the silica gel packets and the model itself, not all customers bother to read or take any notice of these instructions about care and attention required for their "investments". One such customer returned a 370mm long automotive component 5 months later, expecting to proceed with silicone tooling for p.u. castings only to find the model overlength to the tune of 3.5mm. This unfortunate case stresses the importance of keeping our customers well informed, not only of the pros of stereolithography, but of the potential cons also.

Goodbye and many thanks

Ross Nicholls
ross@mnl.co.uk

Malcolm Nicholls Limited
Tel +44 (0) 1789 490382
Fax +44 (0) 1789 490130
www.mnl.co.uk/rapid-prototypes/

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



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