HP Forum Archive 08

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Update: reproduction parts Message #1 Posted by barry on 13 May 2002, 2:54 p.m. in a thread below i mentioned we were considering manufacturing some HP41 repro parts (module port covers & battery port covers firstly); well, the moldmaker wanted $2K+ (doubleouch!!) for each mold; this is way too expensive to even consider using this method that its out of mind; trying to figure another method of making a mold directly from the part that would be usable w/ the injection machines but its possibly impractical. we will still attempt to try to figure a method that might be usefull, and i will post if we come up w/ anything. tnx to all who responded! barry carson city, nv

Re: Update: reproduction parts Message #2 Posted by Iqbal on 13 May 2002, 4:05 p.m., in response to message #1 by barry I wonder if it would be possible to make fiberglass parts? That should be much easier, shouldn't it?

Re: Update: reproduction parts Message #3 Posted by barry on 13 May 2002, 4:32 p.m., in response to message #2 by Iqbal yes iqbal, i will be looking into various other methods of making parts, including fiberglass - but 'glas will be hard to do w/ these smaller parts. tnx, barry carson city, nv

Re: Update: reproduction parts Message #4 Posted by David Smith on 13 May 2002, 5:21 p.m., in response to message #1 by barry I think your only practical alternative is laser stereolithography. A laser beam is scanned over a vat of photo setting polymer and the part is built up as a tray is automatically lowered into the vat.

Re: Update: reproduction parts Message #5 Posted by Andreas Stockburger (Germany) on 14 May 2002, 2:51 a.m., in response to message #1 by barry Hi, A college of mine is a specialist for r/c ship models. He told me to make such things from "resin". He showed me some parts he made. They where absolutly great !!! Perhaps this can help you ! Best regards Andreas

Re: Update: reproduction parts Message #6 Posted by Y K Wong (Singapore) on 14 May 2002, 7:25 a.m., in response to message #5 by Andreas Stockburger (Germany) One of the common problem with the 41's is the Battery I/O Assy - especially the flexiable PCB, can that be reproduced? I am sure many of us would need a replacement. Regards, Y K Wong.

Re: Update: reproduction parts Message #7 Posted by barry on 14 May 2002, 9:33 a.m., in response to message #5 by Andreas Stockburger (Germany) yes, this will be the next method to check out; it could prove useful!

Re: Update: reproduction parts Message #8 Posted by Mark Glusker on 14 May 2002, 11:31 a.m., in response to message #1 by barry $2K for a injection molding tool for the HP41C port cover isn't unreasonable. A tool for the battery holder should be much more expensive. There are ways to cut costs on injection molds - was the quote for a steel or an aluminum tool? Epoxy tools are also possible, provided you don't need that many parts. You really want to end up with a part that has a reasonable color and texture match, and that also has a reasonable chance of snapping in properly. I have experience with other prototyping methods (stereolithography, selective laser sintering, rubber molds to make urethane parts) and they could work, but they will need sanding and painting. You will also need to generate an STL file from a solid modeling CAD package such as Pro/Engineer.

Re: Update: reproduction parts Message #9 Posted by barry on 15 May 2002, 12:11 p.m., in response to message #8 by Mark Glusker this was for a steel mold, and that was w/ us supplying the mold base itself; the $2K isn't unreasonable, but when u figure in how many parts you would have to sell to even make back your investment, it just ain't feasible (if you want to keep the price of a port module cover in the $5.00 range). Basically, standard production methods will involve too much expense to make it worthwhile, you aren't going to sell 300 or 400 port module covers; unless you were the moldmaker yourself (and were running the shooting, too!) the math just doesn't work out. Figure you would sell MAYBE 100+ covers, so it just isn't going to work out via injection molding.

Re: Update: reproduction parts Message #10 Posted by Jeff on 15 May 2002, 11:39 p.m., in response to message #9 by barry One way to help cut cost would be to make several different parts in the same mold rather than making several molds. The math still doesn't add up.

Re: Update: reproduction parts Message #11 Posted by barry on 16 May 2002, 10:31 a.m., in response to message #10 by Jeff the cost isn't in the mold base (which we have many of), but in the reverse engineering in making a print of the part to be manufactured, then CNC'ing the base, including all necessary passageways needed to flow liquid plastic correctly, draft angles for correct part removal, etc. there is much more to it. when u realize what these tool & die makers charge/hour it becomes expensive, especially for a knowledgable one. look at a port module cover as if u had to machine one and the problems become apparent. barry carson city, nv

Re: Update: reproduction parts -- How 'bout recahargable battery packs? Message #12 Posted by Paul Brogger on 16 May 2002, 11:10 a.m., in response to message #1 by barry I haven't read all the posts in response to this one, so maybe my two bits won't be very original, but here goes: I wonder whether someone with hardware savvy could come up with "plug-compatible" battery pack replacements -- maybe lithium-ion high-capacity units that deliver the proper voltage, serve as the appropriate load (when necessary), and have recharging jacks built into integral battery covers? For instance, a "3-N" package for the HP-28 calculators would be great -- less-frequent battery changes might help the battery-door-to-case attachment points live longer. Or a "4-C" replacement for the HP-97? (I mention that 'cause I haven't gotten round to rebuilding my 97's battery pack.) It would be great for those of us who occasionally USE some models to have long-life rechargables that would help extend the calculators' useful lives.

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