Question About Making Injection Molds

[E5i50blitz]

First off, I wanted to say this is a pretty informative site, I've learned a lot already just surfing around.

 

I started making some plastic lures a month or 2 ago, and I find it pretty enjoyable

 

I started right off the bat with a couple aluminum injection molds and it was off to the races. I still have a lot to learn, but I'm making some serviceable looking lures and I want to expand on this.

 

I've done a lot of searching on various molds from the major suppliers, and quite frankly I want to try doing some designs of my own.

 

I don't really want to invest / learn all of the ins and outs of creating silicon molds from hand formed models.

 

The reason for this, is that I have a strong background in injection molded plastic design as well as injection mold design. (small cavitation molds)

 

I own the software (Pro/E) to created the 3d models of the lures I would like to create, and I understand how to split the models in half and provide the CNC shop the negatives that they would need to machine (I cant provide the cutter paths though) I understand the venting process as well as the alignment pins and other issues.

 

My issue, is that I think the cost of machining "custom" molds would be a lot higher than the off the shelf molds you can buy due to the fact that they are one-offs.

 

If I invest in these molds and the action of the lure is wrong, then it's scrap aluminum

 

Should I look at machining plastic molds to lower the material costs for these tests?

 

Is there another way to make prototype molds from 3d models? for injection molded plastic parts we would make 3d SLA models and then make poured RTV molds from them, but once again they are pretty expensive.

 

Just curious if anyone else has gone thru these issues and if there were any other materials or prototype ways to get machined parts turned into molds. I understand that CNC time is going to cost me either way, but I wanted to throw this out there to see if I can keep my prototyping costs down.

 

Frankly I'm just amazed at how low the costs are for "off the shelf" machined molds, I realize their polishing and fit time are minimal and the tolerances are looser but the cost of the aluminum blanks are pretty expensive alone.

 

Once again, nice site and it's great to have a lot of talented people to learn from.

 

 

[Baitjunkys]

First off, I wanted to say this is a pretty informative site, I've learned a lot already just surfing around. I started making some plastic lures a month or 2 ago, and I find it pretty enjoyable I started right off the bat with a couple aluminum injection molds and it was off to the races. I still have a lot to learn, but I'm making some serviceable looking lures and I want to expand on this. I've done a lot of searching on various molds from the major suppliers, and quite frankly I want to try doing some designs of my own. I don't really want to invest / learn all of the ins and outs of creating silicon molds from hand formed models. The reason for this, is that I have a strong background in injection molded plastic design as well as injection mold design. (small cavitation molds) I own the software (Pro/E) to created the 3d models of the lures I would like to create, and I understand how to split the models in half and provide the CNC shop the negatives that they would need to machine (I cant provide the cutter paths though) I understand the venting process as well as the alignment pins and other issues. My issue, is that I think the cost of machining "custom" molds would be a lot higher than the off the shelf molds you can buy due to the fact that they are one-offs. If I invest in these molds and the action of the lure is wrong, then it's scrap aluminum Should I look at machining plastic molds to lower the material costs for these tests? Is there another way to make prototype molds from 3d models? for injection molded plastic parts we would make 3d SLA models and then make poured RTV molds from them, but once again they are pretty expensive. Just curious if anyone else has gone thru these issues and if there were any other materials or prototype ways to get machined parts turned into molds. I understand that CNC time is going to cost me either way, but I wanted to throw this out there to see if I can keep my prototyping costs down. Frankly I'm just amazed at how low the costs are for "off the shelf" machined molds, I realize their polishing and fit time are minimal and the tolerances are looser but the cost of the aluminum blanks are pretty expensive alone. Once again, nice site and it's great to have a lot of talented people to learn from.

you could buy a 3d printer and mold the part in rtv.

[Baitjunkys]

Oh. And your paying for machine time and tool wear the most. That chunk of aluminun is not really that expensive in a small cavity mold.

[DaveMc1]

Most companies offering molds will include a single cavity prototype mold to verify you are happy with the final product. Yes, custom molds can be many times the cost of an off the shelf mold. 

[School Master]

Just do like I do and knock it out of the park on the first shot!! Just kidding, just take your time. I always sketch what I want in the best detail I can. This really helps me narrow down on critical dimensions and the over all look I want. Also, use some of you stock baits for measurements on stuff you aren't sure about. Maybe a diameter of a body, or a thickness of a tail. My last tip would be turn your shading all the way up and make a print of just the bait in a 1:1 scale. It really gives you a good look at what you are going to get. I put every orthagraphic view and some isometric too. Make sure to make it 3d realistic, and print it out. Look measure, look measure make some changes and do it again.

 

With your knowledge of venting and injections molds you shouldn't have to worry about the mold its self going wrong. Good luck with the project. I've down a handfull of molds for myself and it is really really awesome to design and catch fish on something you made. Even better than stock molds. Plus it makes you unique. It can be a chunk of change up front, but if you love the bait, whats 2 3 4 grand to catch a couple more bass. RIGHT? Just kidding again.

 

Oh and like Mr. Junky said, use the 3D printer if you got one. I don't but man do I want one.

[bear21211]

E5i50blitz

When we do custom mold work for customers, there is time that goes into discussing the design and action of the bait and such that the customer wants. With doing this over time we have learned a lot of things to do and not to do to make a bait perform a certain way. That being said if you find someone that knows a little of what they are doing and have been doing it for a while they will be able to help you with your quest, and make your project as easy as possible. As far as cost goes you are correct these molds are extremly cheap for what you are getting. The reason for that is we rely on selling multiples of these molds over the years. When doing custom work the customer is charged for our cad and cam time and then we also charge for our machine time and material. As far as cutter wear well lets see i have been running a lot of my cutters for over 3 years and they have not wore out yet so we do not factor that in. If I am wearing out or breaking cutters that fast I need to be optimizing  my tool paths to eliminate that.

 

I would rather have a detailed drawing with all of the deminsions that you want met of your design to work from than anything else.  We have found using drawings from Cad engineers take us a lot more time to get the mold ready than it does from a drawing. We do not need all of the detail that they put into a drawing. We have to keep it simple as we only need one boundry for our tool path creation and when we deal with there drawings we normally have to go in and remove numerous boundries (lines) that we can not use. We try to saty within about .002 with our tolerences if that woud work for you. We create the 3d model and let you inspect it first. We then will create the mold and calculate all of the tool paths and cut a prototype mold . That mold will be tested here to make sure it works properly then sent to the customer. Sometimes you get lucky and nail it on the first shot . If changes need to be made they should only be minimial and usually the second go is a charm.

 

If we can help or answer any questions give us a shout.

Bear

[Vodkaman]

This early in your lure making experience, it is hard to tell what will swim and what won't, especially if you are looking for a specific movement. I think you should bite the bullet and carve out a master and make some molds for testing your design.

 

With your background, I am sure you know all about rapid prototyping and the companies that provide the service. Use the 3D print-out and make a mold, if you are not comfortable about hand modelling.

 

Of course, if money is no object, then throw it out there and see what comes back

 

Dave

[fishon-son]

..plate alum stock is cheap....really cheap...with that being said  some high rpm and some wd40..yep wd40 sprayed on the alum.it will shine like a babys ass...no polishing...but your better off not going to someone that is in it already..you get your molds at home and if its a hot bait there making it and selling the baits for themselves...everone has a senko and sweet beaver  ect....look for a small router type machine for ur garage..1200.00  will get you going...im not taking anything from anyone here  just voicing my opinion....good luck...gary yamamoto cant stop the copy cats and you wont.....that's what this is about...making it cheaper and having fun

[E5i50blitz]

Thanks for the ideas and input everyone. That's what's great about this site is that you have people who are hobby lure makers as well as professional lure makers that are willing to share some of their expertise that they have learned over many years.

 

My reason for going towards more custom lures instead of something off the shelf is not that I think I am better at designing actions, sink rates, and all of the other properties that make a good lure enticing to fish.

 

I am trying to work on some things that would work well for my hobby (small volume) lure making, that would set them apart from something I could buy off the shelf.

 

For example, I've made 500 or so 7" ribbon tail worms, some with insert molded tails.

When I look at the process I immediately want to add a hand actuated slide in the mold so I can shoot the tails, move the slide and then shoot the top.

Looking in the forums there are some old topics about this but I can't find any off the shelf molds. (This must be how the big lure makers do this, I can't imaging insert molding a 48 cavity ribbon tail worm in the press)

 

The hobby lure making volume should allow me to work on things like hand insert molding other materials (weights, rattles, hooks, eyes, Etc.)

 

I guess I'm trying to find that happy middle ground between off the shelf molds (which are great, but they are deigned for a large volume of customers to do a specific task) and molds that allow me to play around with new ideas and concepts.

 

Let's face it, making lures just for friends and family will never be more economical than just buying them off the shelf.  Sure I have more color options, but I'm looking to create some really unique things that I can't buy. (I am re-living my entrance into fly tying the only way I could justify the expense in my head was by catching fish on unique patterns I could not buy off the shelf! )

 

Thanks for all of the feedback everyone,

Blitz

[fishon-son]

a lot of people sell there plastics local in the bait shops where they live..look at bears bait pouring pots.if you had a lot of molds and sometime a small home company could be fired up...good luck.

[robalo01]

What about an online 3D printing service for the model? Would that be cheaper than having a custom aluminum mold made?

[Frank]

[For example, I've made 500 or so 7" ribbon tail worms, some with insert molded tails.

When I look at the process I immediately want to add a hand actuated slide in the mold so I can shoot the tails, move the slide and then shoot the top.

Looking in the forums there are some old topics about this but I can't find any off the shelf molds. (This must be how the big lure makers do this, I can't imaging insert molding a 48 cavity ribbon tail worm in the press)]

 You mean a mold like this one. Basstackle has a few of them but not to many. I am sure he could make you what you want if he was not so busy. No harm in asking though. http://cdn3.volusion.com/r9tyo.ruqm9/v/vspfiles/photos/4.5inchinjectionworm2color-2.jpg

[E5i50blitz]

Frank, that's exactly what I'm thinking. It would seem cheaper to buy that type of mold instead of a tail mold and a body mold. Not even counting the time to insert everything.

[Frank]

He is the only one I know that has offered those type molds in a small form. He makes big mold with that same type thing. Seems to me that would be the way to go also but people buy tail molds and insert them manually. Kinda like laminate plates to me it's way easier to use the Twinjector. Just think shoot the tail and then use the Twinjector for a three colored bait. Or two colored tails and body for a four colored bait. Endless possibilitys .