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Rapid Prototyping, STMFC, and needed kits
Dave Nelson <muskoka@...>
I enjoyed the discussion on rapid prototyping... seems like things are
progressing nicely from just 5 years ago and it prompts me to wonder -- and
ask -- at what point does a group of STMFC subscribers (or a club) pool
resources to have a missing kit created?
Surely cost will be the major factor, but I'm curious to hear other opinions
as to how far fetched this idea is. Will it take a cost of $3000 for resin
masters to cause something to happen? One could think in terms of how many
$30 kits instead of $$, so $3000 + casting materials is somewhere north of
100 kits. Or does the upfront expense need to go as low as $1000 / > 30
kits? Heck, I've got one car in mind that I'd like 20+ so to my thinking
$1000 is rapidly approaching a one person deal, albeit a bit higher desire
for a car than most, but still within the realm of plausible.
Or do you expect the more traditional approach -- that of a side business by
one slightly entrepreneurial guy to be the more likely path taken?
At what point does it make more sense to switch from resin masters to
styrene molds? Beats me.
And of course the other half of the question is this: are there obvious car
candidates for such a project?
All food for thought.
Dave Nelson
progressing nicely from just 5 years ago and it prompts me to wonder -- and
ask -- at what point does a group of STMFC subscribers (or a club) pool
resources to have a missing kit created?
Surely cost will be the major factor, but I'm curious to hear other opinions
as to how far fetched this idea is. Will it take a cost of $3000 for resin
masters to cause something to happen? One could think in terms of how many
$30 kits instead of $$, so $3000 + casting materials is somewhere north of
100 kits. Or does the upfront expense need to go as low as $1000 / > 30
kits? Heck, I've got one car in mind that I'd like 20+ so to my thinking
$1000 is rapidly approaching a one person deal, albeit a bit higher desire
for a car than most, but still within the realm of plausible.
Or do you expect the more traditional approach -- that of a side business by
one slightly entrepreneurial guy to be the more likely path taken?
At what point does it make more sense to switch from resin masters to
styrene molds? Beats me.
And of course the other half of the question is this: are there obvious car
candidates for such a project?
All food for thought.
Dave Nelson
Jon Miller <atsf@...>
Will it take a cost of $3000 for resin masters to cause something tohappen?<
I was thinking short runs of styrene kits. While resin is fine I'm
thinking styrene would have a more universal appeal.
I think the real slow area here is the computer work with CAD design via
Solidworks. Required for this are access to good plans. I'm already trying
to find some plans for a ATSF Tk-L and not having any luck, at least so far.
Jon Miller
AT&SF
For me time has stopped in 1941
Digitrax, Chief/Zephyr systems, JMRI user
NMRA Life member #2623
Member SFRH&MS
Tom Jones III <tomtherailnut@...>
Styrene masters are still quite expensive to produce, and it requires an
injection moulder to get any quality at all. If you expect to sell at least
2,000 kits, you might recoup the cost of styrene masters. Even with
stereolithography, etc., I would expect a complete set of styrene injection
moulds to cost upwards of $20,000 for a boxcar or other simple structure.
On the other hand, if you don't mind building a resin kit, you can complete
a set of RTV rubber moulds for around $250 per set. If there are not a
tremendous number of undercuts or very tiny detailed parts (like stirrup
steps, etc.), you can expect around 250-500 parts to be produced from a set
of moulds before serious detail deterioration or mould destruction occurs.
Having spent over $10,000 on roof moulds and car end moulds alone with
InterMountain for the R-40-25 PFE reefer the ARM produces, you really have
to be able to move a lot of cars to make it worth it.
Tom Jones III
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Show quoted text
injection moulder to get any quality at all. If you expect to sell at least
2,000 kits, you might recoup the cost of styrene masters. Even with
stereolithography, etc., I would expect a complete set of styrene injection
moulds to cost upwards of $20,000 for a boxcar or other simple structure.
On the other hand, if you don't mind building a resin kit, you can complete
a set of RTV rubber moulds for around $250 per set. If there are not a
tremendous number of undercuts or very tiny detailed parts (like stirrup
steps, etc.), you can expect around 250-500 parts to be produced from a set
of moulds before serious detail deterioration or mould destruction occurs.
Having spent over $10,000 on roof moulds and car end moulds alone with
InterMountain for the R-40-25 PFE reefer the ARM produces, you really have
to be able to move a lot of cars to make it worth it.
Tom Jones III
----- Original Message -----
viaWill it take a cost of $3000 for resin masters to cause something tohappen?<
I was thinking short runs of styrene kits. While resin is fine I'm
thinking styrene would have a more universal appeal.
I think the real slow area here is the computer work with CAD design
Solidworks. Required for this are access to good plans. I'm alreadytrying
to find some plans for a ATSF Tk-L and not having any luck, at least sofar.
Jon Miller <atsf@...>
I would expect a complete set of styrene injection moulds to cost upwardsof $20,000 for a boxcar or other simple structure<
Are you talking metal or Ceramic inserts made via the SLA process?
you can complete a set of RTV rubber moulds for around $250 per set.<Rubber molds are way cheaper than this but then you might be talking
about having them contracted out. The rubber for a box car, for example,
costs about 10 bucks (or less depending on the rubber) assuming you have a
master! You buy it in 55 gallon drums and throw the molds away after a few
shots.
250-500 parts<Not the guys I know<VBG>.
Jon Miller
AT&SF
For me time has stopped in 1941
Digitrax, Chief/Zephyr systems, JMRI user
NMRA Life member #2623
Member SFRH&MS
Dave Nelson <muskoka@...>
Tom Jones III wrote:
masters from which the RTV molds are made and resin kits produced.
Adding you're data, an estimate of resin costs, say the masters cost $3000
and everything for casting another $300. That's 110 $30 kits. Is it
plausible this group alone would sign up for 110+ specific kits? I dunno.
I kinda doubt it, but maybe. And of course at $6300 you need to cover with
210 kits -- much harder to do.
I suppose another way of looking at it is to ask what would a master
craftsman change to create a set of resin masters? If it's less than $3000
then the manual method has the economic advantage (and of course if you
yourself are a master craftsman then obviously in-house work is less cheap).
But the point I was raising is this: at what price break point to a group of
modelers set up to the plate and collectively purchase a custom resin
master? And how far into the future might that occur?
FWIW, I've nothing up my sleeve on this. I'm just curious.
Dave Nelson
Styrene masters are still quite expensive to produce, and it requiresActually I was thinking of the rapid prototyping process to create the
an injection moulder to get any quality at all. If you expect to sell
at least 2,000 kits, you might recoup the cost of styrene masters.
Even with stereolithography, etc., I would expect a complete set of
styrene injection moulds to cost upwards of $20,000 for a boxcar or
other simple structure.
On the other hand, if you don't mind building a resin kit, you can
complete a set of RTV rubber moulds for around $250 per set. If there
are not a tremendous number of undercuts or very tiny detailed parts
(like stirrup steps, etc.), you can expect around 250-500 parts to be
produced from a set of moulds before serious detail deterioration or
mould destruction occurs.
masters from which the RTV molds are made and resin kits produced.
Adding you're data, an estimate of resin costs, say the masters cost $3000
and everything for casting another $300. That's 110 $30 kits. Is it
plausible this group alone would sign up for 110+ specific kits? I dunno.
I kinda doubt it, but maybe. And of course at $6300 you need to cover with
210 kits -- much harder to do.
I suppose another way of looking at it is to ask what would a master
craftsman change to create a set of resin masters? If it's less than $3000
then the manual method has the economic advantage (and of course if you
yourself are a master craftsman then obviously in-house work is less cheap).
But the point I was raising is this: at what price break point to a group of
modelers set up to the plate and collectively purchase a custom resin
master? And how far into the future might that occur?
FWIW, I've nothing up my sleeve on this. I'm just curious.
Dave Nelson
Andy Carlson
Dave,
Virtually all of the patterns made for the resin
manufacturers are produced for very little to no
money, often a few resin kits are offered for payment.
-Andy Carlson
Ojai CA
--- Dave Nelson <muskoka@...> wrote:
toggle quoted message
Show quoted text
Virtually all of the patterns made for the resin
manufacturers are produced for very little to no
money, often a few resin kits are offered for payment.
-Andy Carlson
Ojai CA
--- Dave Nelson <muskoka@...> wrote:
I suppose another way of looking at it is to ask
what would a master
craftsman change to create a set of resin masters?
If it's less than $3000
jaley <jaley@...>
On Apr 23, 4:26pm, Jon Miller wrote:
In my (uneducated) opinion, the problem isn't in the CAD; I can
learn Solidworks pretty quickly, I think. What I CAN'T learn quickly is
how to be a good mold designer. Desigining an injection mold is much more
complex than just cutting a prototypical shape into a piece of metal. Or
so I've been told.
Given that rubber molds are much more forgiving (of undercuts,
etc.) I think that we amateurs are better off doing CAD drawings for
resin masters instead of trying to design injection-molds.
Regards,
-Jeff
--
Jeff Aley jaley@...
DPG Chipsets Product Engineering
Intel Corporation, Folsom, CA
(916) 356-3533
Subject: Re: [STMFC] Rapid Prototyping, STMFC, and needed kitsviaWill it take a cost of $3000 for resin masters to cause something tohappen?<
I was thinking short runs of styrene kits. While resin is fine I'm
thinking styrene would have a more universal appeal.
I think the real slow area here is the computer work with CAD design
Solidworks.Jon,
In my (uneducated) opinion, the problem isn't in the CAD; I can
learn Solidworks pretty quickly, I think. What I CAN'T learn quickly is
how to be a good mold designer. Desigining an injection mold is much more
complex than just cutting a prototypical shape into a piece of metal. Or
so I've been told.
Given that rubber molds are much more forgiving (of undercuts,
etc.) I think that we amateurs are better off doing CAD drawings for
resin masters instead of trying to design injection-molds.
Regards,
-Jeff
--
Jeff Aley jaley@...
DPG Chipsets Product Engineering
Intel Corporation, Folsom, CA
(916) 356-3533
Jon Miller <atsf@...>
I think that we amateurs are better off doing CAD drawings forresin masters instead of trying to design injection-molds.<
Last first, I think the CAD design could be used for either type
project. So once the CAD work was done the car (whatever) could progress
either way.
Designing an injection mold is much more complex than just cutting aprototypical shape into a piece of metal.<
Correct from what I've been told also. There is flow rate and cooling
rate and etc.. Probably 75% skill and 25% magic.
Jon Miller
AT&SF
For me time has stopped in 1941
Digitrax, Chief/Zephyr systems, JMRI user
NMRA Life member #2623
Member SFRH&MS