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Plastics, what technology? - 20-07-05 012.jpg (0/1)

M

Mark

Jan 1, 1970
0
Sorry to be a pain but after my previous post, some doubt has been
cast over whever I am talking about Plastic Injection Moulding or Not.
I am looking to have a similar product to the one shown in the
attached photo, made either here in Spain or in "China" or maybe a
combination of the two (tooling there, moulding here). I have attached
some pictures, (one by one so not to overload anybody) please could
you have a look at the item I am trying to emulate, and look at the
plastics and even more closely at the way the two parts are "welded"
together. There is a couple of the plastic parts (for example where
the mains switch is, which looks like it has been inserted into the
outer case. The plastic is not brittle but feels like some sort of
Nylon. I am totally new to plastics and would really appreciate your
positive input. If there is a better place to post this subject, then
please tell me and I will be gone, thanking you in anticipation.

Mark Scotford
[email protected] (remove the X to reply)
 
S

Spehro Pefhany

Jan 1, 1970
0
Sorry to be a pain but after my previous post, some doubt has been
cast over whever I am talking about Plastic Injection Moulding or Not.
I am looking to have a similar product to the one shown in the
attached photo, made either here in Spain or in "China" or maybe a
combination of the two (tooling there, moulding here). I have attached
some pictures, (one by one so not to overload anybody) please could
you have a look at the item I am trying to emulate, and look at the
plastics and even more closely at the way the two parts are "welded"
together. There is a couple of the plastic parts (for example where
the mains switch is, which looks like it has been inserted into the
outer case. The plastic is not brittle but feels like some sort of
Nylon. I am totally new to plastics and would really appreciate your
positive input. If there is a better place to post this subject, then
please tell me and I will be gone, thanking you in anticipation.

Your binary file is not appropropriate to this (non-binary) newsgroup,
and hence has been stripped before I (and probably many or most
others) could see it.

Perhaps you could upload the jpg files somewhere and post a link?
Alternatively, if you must, you could post it in the newsgroup
alt.binaries.schematics.electronic , where it will show up.


Best regards,
Spehro Pefhany
 
M

Mark

Jan 1, 1970
0
Your binary file is not appropropriate to this (non-binary) newsgroup,
and hence has been stripped before I (and probably many or most
others) could see it.

Perhaps you could upload the jpg files somewhere and post a link?
Alternatively, if you must, you could post it in the newsgroup
alt.binaries.schematics.electronic , where it will show up.


Best regards,
Spehro Pefhany

Thanks Spehro

Appologies to everyone, I have quickly put the pictures onto my web
site instead, they can be found at
http://www.markscotford.com/blower.html
your help would be very much appreciated. If you are a plastics
company, please contact me by email, if you can help us, thanks. We
are looking to have made a minimum of 1K in the first year with a
projected figure of 5K within two or three years.

Mark Scotford
 
S

Spehro Pefhany

Jan 1, 1970
0
Thanks Spehro

Appologies to everyone, I have quickly put the pictures onto my web
site instead, they can be found at
http://www.markscotford.com/blower.html
your help would be very much appreciated. If you are a plastics
company, please contact me by email, if you can help us, thanks. We
are looking to have made a minimum of 1K in the first year with a
projected figure of 5K within two or three years.

Mark Scotford

Hi, Mark:-

Although they probably could be (with tooling an order of magnitude
more expensive), those parts are not injection molded, IMHO. And I
don't think that they are nylon, maybe some flavor of polyethylene.
Probably rotomolded. This is a low-pressure, low-volume process that
is probably suitable for domestic manufacturing in Spain. Tooling
cost, precision, and production rate are all relatively low, parts can
be quite large (like a tank or a whole kayak).


Best regards,
Spehro Pefhany
 
J

john jardine

Jan 1, 1970
0
Mark said:
Sorry to be a pain but after my previous post, some doubt has been
cast over whever I am talking about Plastic Injection Moulding or Not.
I am looking to have a similar product to the one shown in the
attached photo, made either here in Spain or in "China" or maybe a
combination of the two (tooling there, moulding here). I have attached
some pictures, (one by one so not to overload anybody) please could
you have a look at the item I am trying to emulate, and look at the
plastics and even more closely at the way the two parts are "welded"
together. There is a couple of the plastic parts (for example where
the mains switch is, which looks like it has been inserted into the
outer case. The plastic is not brittle but feels like some sort of
Nylon. I am totally new to plastics and would really appreciate your
positive input. If there is a better place to post this subject, then
please tell me and I will be gone, thanking you in anticipation.

Mark Scotford
[email protected] (remove the X to reply)

Google up on "Rotational moulding". Basically they pour a quantity of
plastic powder into a hollow metal mould and then rotate it whilst heating.
Process is ideal for thin walled hollow structures.
The mould tools are quite cheap, as no pressures or high temperatures are
involved. Product quantities in say the hundred or so can be economical.
Don't know where you're from but in UK there are quite a number of
manufacturers.
regards
john
 
P

Pooh Bear

Jan 1, 1970
0
Spehro said:
Hi, Mark:-

Although they probably could be (with tooling an order of magnitude
more expensive), those parts are not injection molded, IMHO. And I
don't think that they are nylon, maybe some flavor of polyethylene.
Probably rotomolded. This is a low-pressure, low-volume process that
is probably suitable for domestic manufacturing in Spain. Tooling
cost, precision, and production rate are all relatively low, parts can
be quite large (like a tank or a whole kayak).

They do indeed look like polyethylene.

What's this 'rotomoulding' ? I'm curious. Might be useful to me too.

Graham
 
S

Spehro Pefhany

Jan 1, 1970
0
They do indeed look like polyethylene.

What's this 'rotomoulding' ? I'm curious. Might be useful to me too.

Graham

Rotomolding = rotational molding. John Jardine described the process.
http://www.rotomolding.org/i4a/pages/index.cfm?pageid=3283 Large
hollow items with fairly thick walls and crude surface finish are
typically made by this process.

For hollow product of smaller size and with a more tooling $$ you can
also consider blow molding, where a molten plastic slug called a
'parison' (of varying cross section, in general) is extruded out, and
then inflated to fill the mold with a blast of compressed air. This
method is used to make millions of plastic bleach containers etc., as
it is relatively fast.


Best regards,
Spehro Pefhany
 
R

Rich Grise

Jan 1, 1970
0
Appologies to everyone, I have quickly put the pictures onto my web
site instead, they can be found at
http://www.markscotford.com/blower.html
your help would be very much appreciated. If you are a plastics
company, please contact me by email, if you can help us, thanks. We
are looking to have made a minimum of 1K in the first year with a
projected figure of 5K within two or three years.

From what I can seee, it looks like plain old ordinary polyethelyne.

For something that size, you might be better off blow molding them,
or even may want to consider fiberglass.

Good Luck!
Rich
 
M

Mark

Jan 1, 1970
0
Google up on "Rotational moulding". Basically they pour a quantity of
plastic powder into a hollow metal mould and then rotate it whilst heating.
Process is ideal for thin walled hollow structures.
The mould tools are quite cheap, as no pressures or high temperatures are
involved. Product quantities in say the hundred or so can be economical.
Don't know where you're from but in UK there are quite a number of
manufacturers.
regards
john
Thanks Lads, I took some semi-professional advise and they also said
it was Rotomolding, but they advised that the quantities we will be
buying may necessitate the use of more than one mould to get the
throughput. We need in the first year 1000 pieces and ramping up to
5000 within most probably 3-4 years. Is Rotomolding the way to go, we
are very happy with its rugged build and would like to go with it, but
is it practical for the numbers I have quoted, TIA.

Mark Scotford
[email protected] (remove the X to reply)
 
J

john jardine

Jan 1, 1970
0
Mark said:
On Sat, 16 Jul 2005 00:48:40 +0100, "john jardine" [ ]
Thanks Lads, I took some semi-professional advise and they also said
it was Rotomolding, but they advised that the quantities we will be
buying may necessitate the use of more than one mould to get the
throughput. We need in the first year 1000 pieces and ramping up to
5000 within most probably 3-4 years. Is Rotomolding the way to go, we
are very happy with its rugged build and would like to go with it, but
is it practical for the numbers I have quoted, TIA.

Mark Scotford
[email protected] (remove the X to reply)

We were looking at rotomoulding something the size of a vacuum cleaner. Some
double curvatures with the odd internal strengthening rib. Material was to
be a high density, cross linked Polyethylene. Tool estimated at £6000.
Looking at the other tools in use I queried where the £6k estimate came
from, as the tooling seemed as technologically sophisticated as glorified
biscuit tins. Quantities were about a 1000-2000 a year.

I'd go the Roto route. Two tools?, no problem, the costings still balance.
Roto gets you moving and buys you time to look around and see if anything
else fits the bill for future higher quantities.

I'd suggest it's pointless carving the design in stone, shelling out say
£25k for a fancy precision tool and then 6 months down the line finding you
would like to alter the plenum chamber to a Mk2, to improve performance and
reduce costs.
By all means invest the money but only after you get some sales history in
the bag.
regards
john
 
M

Mark

Jan 1, 1970
0
Thanks Spehro

Appologies to everyone, I have quickly put the pictures onto my web
site instead, they can be found at
http://www.markscotford.com/blower.html
your help would be very much appreciated. If you are a plastics
company, please contact me by email, if you can help us, thanks. We
are looking to have made a minimum of 1K in the first year with a
projected figure of 5K within two or three years.

Mark Scotford


My customer (new to designs from scratch) wants pricing before he will
commit, the product in question will need 3 parts (1 common part and
2 other parts, one for each of the two models) can anybody give me an
idea of the potential Rotomould toolling costs from the Far East for
this? further information on the product can be found at
http://www.markscotford.com/blower.html
 
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