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Injection Mold in a Haas MiniMill

You learn a lot more if you are doing the machine setup and tuning yourself. I think the most important part of a mold is the gates, and knowing how to use them when running the mold. Getting that right is the most important part of a good running cold runner mold.

That is what I meant, the setup is key, they can be finicky at startup, I was always there at every mold I made to see startup and come back a hour or so later after its stabilized to see how its running check the polymer flow...

Funny thing is I made molds for 7 years and it was only on manual equipment. I only got to dream about using CAD and a cnc machine.
The guy that mentored me had some molds I saw that were all programmed in Gcode or conversational, it was impressive what he got done, you would think they were done in CAD/CAM.
 
you would think they were done in CAD/CAM
It's amazing what we got done with pantographs, files, copy mills and then fingercam on shitty machines like the Bridgeport Interact. I never saw CAM until I worked at a contract shop using MasterCam V2.

When I did my apprenticeship it was Keller aids and grinders. It was pretty high tech when they scanned panels to create toolpaths for stamping dies.

There was a reason die makers were so highly valued and paid back in the day. Now a monkey can be trained to be a die maker if you have an adequate supply of banana's.
 
I was just thinking yesterday how a 3D printer and a copy mill could be an interesting combo for hobbyists, low quantity model-making, etc.
Depending, I have seen people 3D print the prototype cavities and cores, and just put them in a mud set. Super ghetto, but gets you a part that can actually be structurally tested correctly.
 
Hi mhajicek:
The idea of using a 3D printed pattern for copy milling is attractive.
Sadly there's a big problem, and that is that the pattern needs to be super hard, super rigid and super tough, otherwise the tracing stylus just destroys the pattern, especially as it gets skinnier.
When you run a pantograph, you basically uncouple as few axes as you can and then you force the stylus against the pattern to keep the cutter following the contours and stop it from from bouncing around.
It's a good workout...the forces you are trying to control are pretty big, and that's even with a single lip cutter that has no rake and no spiral to snatch at the workpiece

We used a black epoxy whose name now escapes me...you couldn't dent that shit with a ball peen hammer.
It was super expensive and it stank...that's all I really remember.
I don't know if anyone even makes that pattern epoxy anymore.

So it sounds good to just 3D print your shape and then duplicate it with a pantograph, but unfortunately the reality doesn't really work that way.
There are YouBoob videos out there that show guys doing it this way but it only "sort of" works if you don't care about precision.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
 
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We used a black epoxy whose name now escapes me...you couldn't dent that shit with a ball peen hammer.
It was super expensive and it stank...that's all I really remember.
I don't know if anyone even makes that pattern epoxy anymore.
We used a blue Araldite that was painted over the pattern in a thick layer then a filled epoxy was used to create the bulk of the pattern. I just remember the boss bitching about the cost of the blue Araldite but then he was a Scot.
 
The idea of using a 3D printed pattern for copy milling is attractive.
Sadly there's a big problem, and that is that the pattern needs to be super hard, super rigid and super tough, otherwise the tracing stylus just destroys the pattern, especially as it gets skinnier.
Maybe with a pantograph but with tracer mills, this is just wrong. The stylus moves very very easily. You could make the pattern out of paper-mache and it'd work, no problem.

What I see as wrong with the idea is, many of the parts you'd be making are repros of old stuff. Computer-created parts don't cut it. You can tell, easily, that they are not genuine. So making a model out of a 3d printer would be no better than just milling from solid. It'd be yet another step, in fact.

Make the model manually or use a broken part glued together and bondoed up a bit, and I also think this could be a niche market for a few people.

If you're just going to make new-style products, then start with an older nc machine and skip the plastic step, a decent tracer will cost as much as a 1990 Kira or something.
 
Hi EmGo:
Are you talking about a Keller or a Droop and Rein?
Yes the contact pressure on these is a lot lower, but so far as I know these are big complicated machines.

I think Bridgeport may have made an attachment of a more reasonable size, but I'm not sure of that..."Tru Trace" maybe??
This is all a long long time ago.
To top it off. we had a Tree 2 axis mill and we made 3 axis mold cavities for Suzuki mortorcycle taillight lenses on it by
cuttting a pattern of the cavity floor, and a separate pattern of the cavity outline. bolting them together and then mounting them on the table with a stylus on an arm on the quill.
We'd then run a 2 axis program to cover the floor of the cavity and just trace the 3D contour with the quill.

Discing out the cavity with an abrasive disc was part of what we had to get good at.

The good old days.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
 
Are you talking about a Keller or a Droop and Rein?
Yes the contact pressure on these is a lot lower, but so far as I know these are big complicated machines.
Nope. Gorton Tracemaster, Bridgeport had TrueTrace, Monarch had them for lathes with very light touch force, and others. I've only run the Gorton type and we had one on a Clausing but you drove the stylus with very light, fingertip pressure. It would surprise me if Bridgeport were way behind, most direct competitors have pretty similar capabilities.
 
We did break styli on the Zayer copy mill so it had a little wire that broke and stopped the machine. Someone used a thick piece of copper wire that didn't break and the machine proceeded to plunge a 35mm ball nose straight into the die and then bury the Titanic toolholder into the die. When they came in to work in the morning the holder was this molten ball of steel and the die didn't look to good either.
 
I agree school, depending, has just became another business, the education is low, and its government back loans, so the school just lets anyone rip through with minimal skill sets to show for it.
On the plus side the current young generations due to the internet and Youtube, are finding this out and bailing on the "you need college to live well", its BS that has came and went.

If my son doesn't want to learn molding, it is too bad also, a large skill set that not a lot of people know, not passed by this individual.

Also as Donkey mentioned above neither is an "Injection Mold Engineer" but most people I know that do injection mold tooling only machine it. They arent the engineers that actually design and engineer the mold,
I dont know anyone running Autodicks mold flow, and actually engineering the molds, they usually dont even design them, they just machine them, which is a separate skill by itself, not like just cranking out parts.

But I did work as the mold engineer, and i did have to run mold flow software on some molds, after a while you dont really need the engineering its stuck in your head, but its nice to get a better look at where to put air vents,
or if your going to need excess cooling in a core....
Fun fact I tool a cnc course after nearly 20 years in industry and I only learned two things. One the book is bullshit 90% of the time and two I already knew more than the instructor since he kept telling the other students to ask me when they had a question. I tried to get paid for my time , but that wasn't appreciated.
 
Hi again Donkey and Houdini:
I too, did both the mold design and the mold making.
I often did the part design too, or at least the "design for molding" and had to learn sometimes painfully what works and what does not.

In my experience, the jams you get yourself back out of are the most valuable lessons you'll ever learn in a profession like Plastics Engineering, and if you got to fuck it up in every sub domain, you have a better chance to get good at all of it, and it informs your designs in a way you simply cannot duplicate with any other learning process.

I was most fortunate, early in my moldmaking career, to work in a place that did their own molding too, so I got to see the successes and the failures too.
I got to see just how an impatient monkey can fuck up an expensive tool, I got to see what sophisticated cooling and venting and gating can do to make a mold run well, I got to see how it all works in an integrated way to get those 5 cent plastic parts, all good for tolerances and molded in the proper part of the processing window so they had the material properties the customer wanted.

I got to see every dirty trick a molder can use to get parts out of a substandard mold and I got to see which corners they routinely cut to pull out a cheaper part so they can make more money.
Super valuable lessons all...I'm glad I was lucky enough to get them.

Now I have a whole new generation of kids to acquaint with all this tribal knowledge...many of them are super smart kids, but they really have no idea of what they don't know, and when I call them on something they pulled out of a text somewhere, they are baffled that the reality could be so different from what they got from the book.
The odd one laments "But the book SAYS..."

Learning how to teach the new kids has been as much of an education for me as acquiring my own knowledge has been.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
I truly think teaching a young inquisitive mind can be the greatest learning opportunity.
 
Fun fact I tool a cnc course after nearly 20 years in industry and I only learned two things. One the book is bullshit 90% of the time and two I already knew more than the instructor since he kept telling the other students to ask me when they had a question. I tried to get paid for my time , but that wasn't appreciated.
What's funny a similar thing happened to me in my Photoshop class, The schedule showed a Photoshop class was next after Christmas break.
So I looked at the list of books for the class, pre bought them, and an advanced book, and downloaded a copy of Photoshop off the net.
I think 3 books all together, I read all 3 , and 2 of them I went through almost all the samples.
It was only like a week later, I don't even think 2, but by the time the class was going, each project I was doing what was asked, but then a ton more advanced stuff.
Then people started asking me what I was doing to get the effects, the teacher got mad and told people to ask him, when they did he didn't know.
This was one of the teachers that eventually complained to the school about me when I came back. :bawling: :D
 
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