Injection molding forum?
--Doesn't seem to be one on usenet (!!) Can someone suggest a place
to discuss this topic? I'm taking a whack at making a small injection molding die for a small, but fairly odd piece.. -- "Steamboat Ed" Haas : Blue Cross socks us Hacking the Trailing Edge! : $23,000/yr!! ... www.nmpproducts.com ---Decks a-wash in a sea of words--- |
Injection molding forum?
steamer wrote:
--Doesn't seem to be one on usenet (!!) Can someone suggest a place to discuss this topic? I'm taking a whack at making a small injection molding die for a small, but fairly odd piece.. I could probably help out a little Ed. I've done a lot of things but one of them was 30 years designing and building injection molds. -- John R. Carroll |
Injection molding forum?
On Tue, 16 Feb 2010 09:53:59 -0800, "John R. Carroll"
wrote: steamer wrote: --Doesn't seem to be one on usenet (!!) Can someone suggest a place to discuss this topic? I'm taking a whack at making a small injection molding die for a small, but fairly odd piece.. I could probably help out a little Ed. I've done a lot of things but one of them was 30 years designing and building injection molds. I have a post-grad certificate in plastic injection mold design, but John would probably be a better bet. |
Injection molding forum?
steamer writes:
Can someone suggest a place to discuss this topic? I would also like to know some small-scale feasibility. I'm paying $25/each for injection-molded camera hot-shoe connectors for which I have found exactly one supplier in the universe. |
Injection molding forum?
Richard J Kinch wrote:
steamer writes: Can someone suggest a place to discuss this topic? I would also like to know some small-scale feasibility. I'm paying $25/each for injection-molded camera hot-shoe connectors for which I have found exactly one supplier in the universe. That's not a bad price if the contacts are inmolded. -- John R. Carroll |
Injection molding forum?
I could probably help out a little Ed. I've done a lot of things but one of them was 30 years designing and building injection molds. I have a post-grad certificate in plastic injection mold design, but John would probably be a better bet. I've got a few years under my belt running injection mold presses. Only complete hydraulic, no toggles. Mostly on HPM and Cincinnati. My focus was on running them faster, adding pickers, going to runnerless molds, etc. Not much prototype work. Karl |
Injection molding forum?
--Aha! Looks like RCM is da place after all. Well I'm trying to make
a die to make these: http://www.nmpproducts.com/nmp02.htm --I dreamed this up more than a decade ago and I've given up on trying to get a die made that costs less than any potential worldwide sales of the widget in question. Sooo I've managed to carve out the fin part of the cavity with a Bridgeport and my little Sherline rotary table (total depth of fins not right due to short endmill; longer ones back ordered). But making the 3 inserts (and the plate that will hold them accurately) is getting a bit tricky. Will try to post some photos to my blog in a day or two. --I'm thinking of pouring in an epoxy of some kind as I really don't want to injection mold them until I get the geometry of the die just right. Gotta figure out what's available that has the correct durometer; something like nylon would be ideal. --I've got one of those 1/3 oz injection molding machines that a now-gone supplier of same for trade schools sold many moons ago but it needs to be thoroughly gone thru as it's been sitting idle under the workbench forever; that's another can of worms I'll need to open eventually.. -- "Steamboat Ed" Haas : Blue Cross socks us Hacking the Trailing Edge! : $23,000/yr!! ... www.nmpproducts.com ---Decks a-wash in a sea of words--- |
Injection molding forum?
steamer wrote: --Aha! Looks like RCM is da place after all. Well I'm trying to make a die to make these: http://www.nmpproducts.com/nmp02.htm --I dreamed this up more than a decade ago and I've given up on trying to get a die made that costs less than any potential worldwide sales of the widget in question. Sooo I've managed to carve out the fin part of the cavity with a Bridgeport and my little Sherline rotary table (total depth of fins not right due to short endmill; longer ones back ordered). But making the 3 inserts (and the plate that will hold them accurately) is getting a bit tricky. Will try to post some photos to my blog in a day or two. --I'm thinking of pouring in an epoxy of some kind as I really don't want to injection mold them until I get the geometry of the die just right. Gotta figure out what's available that has the correct durometer; something like nylon would be ideal. --I've got one of those 1/3 oz injection molding machines that a now-gone supplier of same for trade schools sold many moons ago but it needs to be thoroughly gone thru as it's been sitting idle under the workbench forever; that's another can of worms I'll need to open eventually.. You are aware of the widely available and very inexpensive quick stop clamp nuts: http://www.use-enco.com/CGI/INSRIT?P...&PMPXNO=945606 (Currently a whopping $4.25) Or the slightly fancier and more difficult to install version: http://www.use-enco.com/CGI/INSRIT?P...&PARTPG=INSRHI |
Injection molding forum?
On 17 Feb 2010 17:40:36 GMT, steamer wrote:
--Aha! Looks like RCM is da place after all. Well I'm trying to make a die to make these: http://www.nmpproducts.com/nmp02.htm Cool. --I dreamed this up more than a decade ago and I've given up on trying to get a die made that costs less than any potential worldwide sales of the widget in question. Sooo I've managed to carve out the fin part of the cavity with a Bridgeport and my little Sherline rotary table (total depth of fins not right due to short endmill; longer ones back ordered). But making the 3 inserts (and the plate that will hold them accurately) is getting a bit tricky. Will try to post some photos to my blog in a day or two. Steel or aluminum? You planning on unscrewing a threaded bit to get it out? --I'm thinking of pouring in an epoxy of some kind as I really don't want to injection mold them until I get the geometry of the die just right. Gotta figure out what's available that has the correct durometer; something like nylon would be ideal. Have you looked at cast urethane (you probably have a vacuum pump for degassing)? For a test run you could also consider doing rapid protyping, but it will be a few hundred dollars cost most likely. --I've got one of those 1/3 oz injection molding machines that a now-gone supplier of same for trade schools sold many moons ago but it needs to be thoroughly gone thru as it's been sitting idle under the workbench forever; that's another can of worms I'll need to open eventually.. Is 1/3-oz enough? |
Injection molding forum?
steamer writes:
http://www.nmpproducts.com/nmp02.htm Cute, but the this threaded feature on the Bridgeport is an obsolete analog item. Replace it with a flatted rod and thumbscrew clamp, and measure with a DRO, better/faster/cheaper. |
Injection molding forum?
steamer wrote:
--Aha! Looks like RCM is da place after all. Well I'm trying to make a die to make these: http://www.nmpproducts.com/nmp02.htm Lordy Ed, I remember when this first appeared in Machine Design! Hope you finally get it off the ground and make some $$ with it! Jon |
Injection molding forum?
Pete C. wrote:
You are aware of the widely available and very inexpensive quick stop clamp nuts: --Yeah, yeah, been there, done that. Ever have one slip on you and go .05" too deep? ;-) -- "Steamboat Ed" Haas : Blue Cross socks us Hacking the Trailing Edge! : $23,000/yr!! ... www.nmpproducts.com ---Decks a-wash in a sea of words--- |
Injection molding forum?
Spehro Pefhany wrote:
On 17 Feb 2010 17:40:36 GMT, steamer wrote: --Aha! Looks like RCM is da place after all. Well I'm trying to make a die to make these: http://www.nmpproducts.com/nmp02.htm Cool. --I dreamed this up more than a decade ago and I've given up on trying to get a die made that costs less than any potential worldwide sales of the widget in question. Sooo I've managed to carve out the fin part of the cavity with a Bridgeport and my little Sherline rotary table (total depth of fins not right due to short endmill; longer ones back ordered). But making the 3 inserts (and the plate that will hold them accurately) is getting a bit tricky. Will try to post some photos to my blog in a day or two. Steel or aluminum? You planning on unscrewing a threaded bit to get it out? --Aluminum. Threading occurs after molding, when two parts are snapped together; makes the making of the mold much easier. --I'm thinking of pouring in an epoxy of some kind as I really don't want to injection mold them until I get the geometry of the die just right. Gotta figure out what's available that has the correct durometer; something like nylon would be ideal. Have you looked at cast urethane (you probably have a vacuum pump for degassing)? --Yes; have vac pump but want to avoid the step if possible. For a test run you could also consider doing rapid protyping, but it will be a few hundred dollars cost most likely. --Heh. For my next project I'm going to build a Mendel (http://objects.reprap.org/wiki/Mechanical_construction) so's I can make 'em that way but I really don't think the resolution is good enough yet.. --I've got one of those 1/3 oz injection molding machines that a now-gone supplier of same for trade schools sold many moons ago but it needs to be thoroughly gone thru as it's been sitting idle under the workbench forever; that's another can of worms I'll need to open eventually.. Is 1/3-oz enough? --Oh yeah; plenty big enough. -- "Steamboat Ed" Haas : Blue Cross socks us Hacking the Trailing Edge! : $23,000/yr!! ... www.nmpproducts.com ---Decks a-wash in a sea of words--- |
Injection molding forum?
Richard J Kinch wrote:
steamer writes: http://www.nmpproducts.com/nmp02.htm Cute, but the this threaded feature on the Bridgeport is an obsolete analog item. Replace it with a flatted rod and thumbscrew clamp, and measure with a DRO, better/faster/cheaper. --Different strokes for different folks; I've used the prototype for over a decade: no complaints.. -- "Steamboat Ed" Haas : Blue Cross socks us Hacking the Trailing Edge! : $23,000/yr!! ... www.nmpproducts.com ---Decks a-wash in a sea of words--- |
Injection molding forum?
Jon Anderson wrote:
steamer wrote: --Aha! Looks like RCM is da place after all. Well I'm trying to make a die to make these: http://www.nmpproducts.com/nmp02.htm Lordy Ed, I remember when this first appeared in Machine Design! Hope you finally get it off the ground and make some $$ with it! --Heh. Yah, sometimes it takes me a while to get around to something but the time has finally come for this one! -- "Steamboat Ed" Haas : Blue Cross socks us Hacking the Trailing Edge! : $23,000/yr!! ... www.nmpproducts.com ---Decks a-wash in a sea of words--- |
Injection molding forum?
steamer wrote: Pete C. wrote: You are aware of the widely available and very inexpensive quick stop clamp nuts: --Yeah, yeah, been there, done that. Ever have one slip on you and go .05" too deep? ;-) Nope. |
Injection molding forum?
steamer wrote: Spehro Pefhany wrote: On 17 Feb 2010 17:40:36 GMT, steamer wrote: --Aha! Looks like RCM is da place after all. Well I'm trying to make a die to make these: http://www.nmpproducts.com/nmp02.htm Cool. --I dreamed this up more than a decade ago and I've given up on trying to get a die made that costs less than any potential worldwide sales of the widget in question. Sooo I've managed to carve out the fin part of the cavity with a Bridgeport and my little Sherline rotary table (total depth of fins not right due to short endmill; longer ones back ordered). But making the 3 inserts (and the plate that will hold them accurately) is getting a bit tricky. Will try to post some photos to my blog in a day or two. Steel or aluminum? You planning on unscrewing a threaded bit to get it out? --Aluminum. Threading occurs after molding, when two parts are snapped together; makes the making of the mold much easier. In that case, forget injection molding and think extrusion. You've got something that's basically like a big T05 heatsink, so you should be able to extrude as a complete part (no snap together) and then slice into the appropriate lengths. You could also just lathe and mill it with a 4th axis, taking a solid plastic rod, bore the center hole on the lathe, then put in 4th axis on the mill and mill the fins. A 24" rod should yield like 45 parts. |
Injection molding forum?
On Feb 16, 11:15*am, steamer wrote:
* * * * --Doesn't seem to be one on usenet (!!) *Can someone suggest a place to discuss this topic? I'm taking a whack at making a small injection molding die for a small, but fairly odd piece.. -- * * * * "Steamboat Ed" Haas * * * * : *Blue Cross socks us * * * * * Hacking the Trailing Edge! *: *$23,000/yr!! ... * * * * * * * * * * * * *www.nmpproducts.com * * * * * * * * * *---Decks a-wash in a sea of words--- If you haven't already seen it, then this site might interest you: http://www.hobbymolding.com/forum/ |
Injection molding forum?
Pete C. wrote:
In that case, forget injection molding and think extrusion. You've got something that's basically like a big T05 heatsink, so you should be able to extrude as a complete part (no snap together) and then slice into the appropriate lengths. --The thought has crossed my mind but again it becomes a part best made by experts and the price goes up accordingly. I want to do it all 'in house' so's it becomes more cost effective. Die's almost done now; hope to get some epoxy parts out of it soon. You could also just lathe and mill it with a 4th axis, taking a solid plastic rod, bore the center hole on the lathe, then put in 4th axis on the mill and mill the fins. A 24" rod should yield like 45 parts. --Not set up to do this either. Sigh.. -- "Steamboat Ed" Haas : Blue Cross socks us Hacking the Trailing Edge! : $23,000/yr!! ... www.nmpproducts.com ---Decks a-wash in a sea of words--- |
Injection molding forum?
On 19 Feb 2010 20:30:44 GMT, steamer wrote:
Pete C. wrote: In that case, forget injection molding and think extrusion. You've got something that's basically like a big T05 heatsink, so you should be able to extrude as a complete part (no snap together) and then slice into the appropriate lengths. --The thought has crossed my mind but again it becomes a part best made by experts and the price goes up accordingly. I want to do it all 'in house' so's it becomes more cost effective. Die's almost done now; hope to get some epoxy parts out of it soon. Instead of epoxy, do a search for "casting resin" on Ebay. A half-gallon kit is $30 (plus shipping), a two-gallon kit is $80. Much thinner than any epoxy I've used so degassing may not be necessary, hardens in about five minutes, no significant exotherm in small parts, nice off-white color, tough product. Just a satisfied customer. Best -- Terry |
Injection molding forum?
Terry wrote:
Instead of epoxy, do a search for "casting resin" on Ebay. A half-gallon kit is $30 (plus shipping), a two-gallon kit is $80. Much thinner than any epoxy I've used so degassing may not be necessary, hardens in about five minutes, no significant exotherm in small parts, nice off-white color, tough product. --Thanks; will do! -- "Steamboat Ed" Haas : Blue Cross socks us Hacking the Trailing Edge! : $23,000/yr!! ... www.nmpproducts.com ---Decks a-wash in a sea of words--- |
Injection molding forum?
--OK gang here's a link to a couple of photos:
http://www.flickr.com/photos/steamboat_ed/ -- "Steamboat Ed" Haas : Blue Cross socks us Hacking the Trailing Edge! : $23,000/yr!! ... www.nmpproducts.com ---Decks a-wash in a sea of words--- |
Injection molding forum?
--Update update: finished the silver soldering for the weirder of
the inserts today and have only to thread two holes and bore an entry port for injection molding nozzle to finish the die. --Did quite a bit of searching for pelletized Nylon and finally settled on a supplier. But there's a minimum purchase quantity of 55 pounds so I'm going to wind up with a wee bit more than I need! Anyone want some?? -- "Steamboat Ed" Haas : Blue Cross socks us Hacking the Trailing Edge! : $23,000/yr!! ... www.nmpproducts.com ---Decks a-wash in a sea of words--- |
Injection molding forum?
In article ,
steamer wrote: --Did quite a bit of searching for pelletized Nylon and finally settled on a supplier. But there's a minimum purchase quantity of 55 pounds so I'm going to wind up with a wee bit more than I need! Anyone want some?? I have too many projects and not enough time, but I've always thought about using some of the "easier" recyclable thermoplastics - though I don't really know what I'd be getting into there. Figure some sort of process like shred, blow dry hot nitrogen through to dry and eventually melt (guessing that oxygen may be an issue with some plastics at high temperatures), perhaps an intermediate extrude a rod to make pellets step, perhaps directly to molding. Figure on making some really hefty plastic objects (no point in conserving feedstock if, as last I recall, recycling centers are not able to give most of the stuff away). Of course, then I want the spiffy selective membrane tubes to make the nitrogen, and all anybody wants to sell is the entire packaged nitrogen system. -- Cats, coffee, chocolate...vices to live by |
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