Designing molds feasibility?

Jump to latest Follow Reply
I

intrepidaf

Member
Mar 1, 2024
30
17
raleigh, nc, usa
I 3d model. Polymodel, sculpt, voxel, nurbs, CAD, etc. I also have a few 3d printers where I model replacement RC parts and print them myself.

Unfortunately, I don't have a CNC machine and you cant mold pellets from a 3d printed mold haha. I would like to take a few molds I designed and then see if I can find a business or individual that would machine them for me (at a cost that is worth it to them of course). A quick google search told me I don't have any idea what exactly I need to search to find that type of service.

Are there any obvious issues with finding someone with the equipment willing to machine my designs?

I'm pretty sure I need 440C stainless steel.

I was surprised to find there weren't many quality options for pellet molds.
 
In the DIY ammo space there are a few companies which do make casting molds I can recall. NOE (https://noebulletmolds.com/site/product-category/224/) , MP molds do it. There is one pellet die makers for pellets (swaging type) and there are companies like GMI (which I am part of) specialized only with slug forming die sets.

The obvious issue is that there is a lot of machining rejection which you cannot recover. I had experiences of scrapping 1 half of the pellet casting and swaging die because there was alignment error, thus resulting in entire set getting scrapped.

Also tolerances are crucial, no 2 molds are the same. And machining is expensive. 440C is not the ideal material as it is heavy and not ideal for heat dissipation. Thus there are challenges with precision engineering and machining of molds, but a great deal of companies do exist which can help.
 
  • Like
Reactions: Spinach and RM.510bigbore
Upvote 0
Engg.Ken said:
In the DIY ammo space there are a few companies which do make casting molds I can recall. NOE (https://noebulletmolds.com/site/product-category/224/) , MP molds do it. There is one pellet die makers for pellets (swaging type) and there are companies like GMI (which I am part of) specialized only with slug forming die sets.

The obvious issue is that there is a lot of machining rejection which you cannot recover. I had experiences of scrapping 1 half of the pellet casting and swaging die because there was alignment error, thus resulting in entire set getting scrapped.

Also tolerances are crucial, no 2 molds are the same. And machining is expensive. 440C is not the ideal material as it is heavy and not ideal for heat dissipation. Thus there are challenges with precision engineering and machining of molds, but a great deal of companies do exist which can help.
Click to expand...
I can only imagine how much it hurts to run into an error while machining. Luckily 3d printing stuff is pretty cheap and the biggest setback is time lost.

You guys have some solid products. The website is really well put together. Was also able to find some good videos of people using the molds.

If I picked up a swaging kit it would likely be GMI! I'm not yet gonna give up trying to find someone to machine my design. I modeled it similar to the thormoldsinc 20 pellet mold, with some quality-of-life improvements.

I appreciate you taking the time to comment. Thanks for your expertise!
 
Upvote 0
Designing sounds easy, I am a mechanical CAD designer myself with some 40+ years around my neck and worked on really large CAD ecosystems.
Programming CNC toolpaths is easy, also cutting metal on CNC machines.
The problems starts when the mold/die is finished, you got your batch of pellets and you start testing. And when you realize your pellets nothing better then the existing lineup off the shelf.
Then what?
The "existing common" shape of the pellets exist over 100 years, so far everybody is just copying and cloning, but there is no revolutionary performance so far.
 
  • Like
Reactions: Airgun-hobbyist
Upvote 0
bigHUN said:
Designing sounds easy, I am a mechanical CAD designer myself with some 40+ years around my neck and worked on really large CAD ecosystems.
Programming CNC toolpaths is easy, also cutting metal on CNC machines.
The problems starts when the mold/die is finished, you got your batch of pellets and you start testing. And when you realize your pellets nothing better then the existing lineup off the shelf.
Then what?
The "existing common" shape of the pellets exist over 100 years, so far everybody is just copying and cloning, but there is no revolutionary performance so far.
Click to expand...
That's a valid point. I hadn't thought about the possibility of making higher-quality pellets than those available in stores. My main focus was on creating a functional mold in case I ever needed to make pellets myself due to lack of availability. It seems like it might be more economical to instead purchase more pellets than I'll ever use.
 
  • Like
Reactions: beerthief
Upvote 0
intrepidaf said:
That's a valid point. I hadn't thought about the possibility of making higher-quality pellets than those available in stores. My main focus was on creating a functional mold in case I ever needed to make pellets myself due to lack of availability. It seems like it might be more economical to instead purchase more pellets than I'll ever use.
Click to expand...
@interpidaf I am not sure what "higher quality" you wish to achieve. For me its all about repeatable consistency, If a certain size is bad then it will be consistently bad, but it will be precise in its grouping. The quest is about identical parts x 1 million before a die gets worn. And its difficult, Its a function of time.
 
Upvote 0
intrepidaf said:
I 3d model. Polymodel, sculpt, voxel, nurbs, CAD, etc. I also have a few 3d printers where I model replacement RC parts and print them myself.

Unfortunately, I don't have a CNC machine and you cant mold pellets from a 3d printed mold haha. I would like to take a few molds I designed and then see if I can find a business or individual that would machine them for me (at a cost that is worth it to them of course). A quick google search told me I don't have any idea what exactly I need to search to find that type of service.

Are there any obvious issues with finding someone with the equipment willing to machine my designs?

I'm pretty sure I need 440C stainless steel.

I was surprised to find there weren't many quality options for pellet molds.
Click to expand...
If I remember correctly Mr. Hollowpoint tried experimenting with 3d mold making. I believe heat and materials available was the issue? Of course he has his business to run and no longer has the time to invest in it.
 
  • Like
Reactions: intrepidaf
Upvote 0
Engg.Ken said:
@interpidaf I am not sure what "higher quality" you wish to achieve. For me its all about repeatable consistency, If a certain size is bad then it will be consistently bad, but it will be precise in its grouping. The quest is about identical parts x 1 million before a die gets worn. And its difficult, Its a function of time.
Click to expand...
I was quoting this observation bigHUN made: "And when you realize your pellets nothing better then the existing lineup off the shelf. Then what?"

Neither the thought nor idea had crossed my mind. =)
 
Upvote 0
NOE and MP won't do one-off's, they will do a run if enough people will commit to a mold.

I've got a dozen such molds in group runs for PB's.

Aluminum is by far the best material to make prototype molds from. It's not perfect but it's far and away superior to steel for ease of cut, cherry life and errosive diameter shrink than harder materials.

New EDM cut profiles for cherries are making fast-prototyping a reality in industry.
 
  • Like
Reactions: dgeesaman, RM.510bigbore and intrepidaf
Upvote 0
Firewalker said:
NOE and MP won't do one-off's, they will do a run if enough people will commit to a mold.

I've got a dozen such molds in group runs for PB's.

Aluminum is by far the best material to make prototype molds from. It's not perfect but it's far and away superior to steel for ease of cut, cherry life and errosive diameter shrink than harder materials.

New EDM cut profiles for cherries are making fast-prototyping a reality in industry.
Click to expand...
Looks like Thor is machining the cavities directly into the die halves. Claiming .0005" dimensional accuracy at worst. (If/when I get one, I may put it on our CMM at work can see just how good it is)

Is mold-making using a carbide cherry and double-acting vise a more accurate method? Or just old school?
 
Last edited:
  • Like
Reactions: Firewalker
Upvote 0
dgeesaman said:
.... Claiming .0005" dimensional accuracy at worst. .... I may put it on our CMM ....
Click to expand...
I was a CNC programmer 4 and 5 axis CNC machines in a EDM company over ten years ( TIER1, that was before I moved out from MFG and spent the rest of my carrier as a new product development designer strictly for OEM).
The best precision you get by - not cutting directly the metal but cut the electrodes (copper and graphite) and remove the material (EDM). For a pellet shape cavities I would assume two electrodes at least. And then polish the metal to whatever finish you like.
My concern with these molds is not a precision on molds or per cavity, but the amo performance on POI.
If they copy or clone the existing pellets shape into new molds .... then wtf we can expect to perform better?
 
  • Wow
Reactions: Firewalker
Upvote 0
bigHUN said:
I was a CNC programmer 4 and 5 axis CNC machines in a EDM company over ten years ( TIER1, that was before I moved out from MFG and spent the rest of my carrier as a new product development designer strictly for OEM).
The best precision you get by - not cutting directly the metal but cut the electrodes (copper and graphite) and remove the material (EDM). For a pellet shape cavities I would assume two electrodes at least. And then polish the metal to whatever finish you like.
My concern with these molds is not a precision on molds or per cavity, but the amo performance on POI.
If they copy or clone the existing pellets shape into new molds .... then wtf we can expect to perform better?
Click to expand...

Sorry, I don't understand, your gunna' have to dumb that down a bit for this ole country boy...
 
Upvote 0
dgeesaman said:
Looks like Thor is machining the cavities directly into the mold halves. Claiming .0005" dimensional accuracy at worst. (If/when I get one, I may put it on our CMM at work can see just how good it is)

Is mold-making using a carbide cherry and double-acting vise a more accurate method? Or just old school?
Click to expand...

This is the modern way, LEE does this too since the blanks are identical, the bit routes the same design again and again.

Cherries and closing the halves is still a great way to enter the field but there is potential for debris/swarf to foul the block.
 
  • Like
Reactions: RM.510bigbore and dgeesaman
Upvote 0
I’ve considered designing my own split die and just wondering which type of die manufacturer makes sense to talk with. By directly machining the cavity you would have the huge advantage of being able to make a multi-cavity die with a variety of designs for testing.

But if the old cherry and split vise or sinker EDM methods produce higher quality then maybe that would make sense for final die production.

On the other hand if there is a practical limit to swaged lead that can’t take advantage of the most accurate dies then maybe it’s moot. My technical background is rotating machinery not swaging.
 
Last edited:
Upvote 0
I edited my posts to say dies since everything I’m interested in is swaging cold lead. I likely got led astray because Thor produces slug and pellet swaging dies but calls themselves Thor Molds, which is likely a translation issue.
(Thor does sell some casting molds for making rods suitable for swaging and I believe I saw a post pouring molten lead into a Thor die - so that muddies things up quite a bit)
 
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu