Just got an Injection Molding machine and looking for Ideas
- Thread starter DinoDino
- Start date
jake88
Sr Member
I would imagine it depends on the molten heat of the media going into the mold. And will aluminum warp under high heat? That’s why the engineers get the big bucks.
drusselmeyer
Master Member
What would be great is to resurrect the forgotten technology of semi-flexible graphite molds.
This tech offered the option of undercuts.
This tech offered the option of undercuts.
Hello all. I have not been on the forums lately because work was keeping me super busy. But I wanted to say thank you all for the ideas. I am considering them all. I wanted to give a little more information as a few people mentioned some important facts about how challenging this can be. I completely agree that this is not a simple task and I am not taking it on lightly.
The past 14 years I have been a design engineer and now a manager of engineers and a prototyping shop. My work designs parts that we send out to be injection molded. We want to learn to design better injection molded parts and bring some prototyping in house, so learning to do this is related to my job. I also want to learn this because it will make be a better engineer.
As for making the molds. We have a machine shop in house which we regularly machine aluminum and stainless steel parts. So we have some basic capabilities to make the molds ourselves. That being said machining a mold is not the same as machining the parts we normally do. In addition to this designing a mold is a skill all on its own. But that is part of the reason I want to find some fun projects to practice with.
We did a very simple test part of a guitar pick and that came out just okay. We were testing out a method of designing a mold and 3d printing it out of a special material on our resign 3d printer. Then putting that on the injection molding machine and molding parts. This is not our original idea by any means and you can google it and read some white papers on the process. The molds dont last super long (100-1000 parts), but it allows us to modify and test our mold designs quickly too. Then we can go to machining an aluminum mold. I dont think we would likely make any steel molds because the quantities of parts we will make are not going to be high enough to justify the effort.
The next part we are working on is part of a old Pinball machine. This part is very simple and should be a good test. We are going to machine an aluminum mold for this. Hopefully I have some photos to share next week.
The past 14 years I have been a design engineer and now a manager of engineers and a prototyping shop. My work designs parts that we send out to be injection molded. We want to learn to design better injection molded parts and bring some prototyping in house, so learning to do this is related to my job. I also want to learn this because it will make be a better engineer.
As for making the molds. We have a machine shop in house which we regularly machine aluminum and stainless steel parts. So we have some basic capabilities to make the molds ourselves. That being said machining a mold is not the same as machining the parts we normally do. In addition to this designing a mold is a skill all on its own. But that is part of the reason I want to find some fun projects to practice with.
We did a very simple test part of a guitar pick and that came out just okay. We were testing out a method of designing a mold and 3d printing it out of a special material on our resign 3d printer. Then putting that on the injection molding machine and molding parts. This is not our original idea by any means and you can google it and read some white papers on the process. The molds dont last super long (100-1000 parts), but it allows us to modify and test our mold designs quickly too. Then we can go to machining an aluminum mold. I dont think we would likely make any steel molds because the quantities of parts we will make are not going to be high enough to justify the effort.
The next part we are working on is part of a old Pinball machine. This part is very simple and should be a good test. We are going to machine an aluminum mold for this. Hopefully I have some photos to share next week.
joberg
Legendary Member
Eager to see your next update and the results of molding that Pinball machine part. I think (I could be wrong) that you're the first member to explore and start making parts using a injection molding machine. Not for the faint of heart in terms of design, engineering and cost as you know very well.
drusselmeyer
Master Member
How can we participate?
I am looking for good ideas for parts which would be worth my time to injection mold. It takes quite a bit of work to get to the point where I can mold the parts. So I was hoping people would have ideas of parts which I could share with the community.
Also, it is always nice when people cheer you on and say positive things about the work you do. So if you think what I am doing is cool, leave me a note.
I made some great progress this week and I wanted to share so photos. I wanted to start by showing the first real part I am going to try injection molding. A friend has a pinball collection and this is a part he needed. I tried 3d printing some and the results were fine, but not perfect. Also, pinball machines are rough on parts. Having a metal ball bouncing around tends to break things. So it isn't crazy to think I will need to make a few of these.
He actually wants this part in a solid yellow color with a decal on the top. I will get back to that in a later post. But for now this is the shape I am going for.
I started out with modeling the part I wanted. Then I 3d printed a few so I could make sure my model was correct. I used that CAD model to design the injection mold. I am new to designing molds and there is a ton of details that go into making a good mold. But I learn best by doing things and making mistakes.
Then I go some left over aluminum from another project. It was thicker than I would have liked but its not a big deal to do a little extra machining. The mold is 6x5x1 in size and I started with this block which was 7x6x1.5
Next I machined the top side. I used a Haas Mini Mill 2 to do the machining. I held the material in a Orange vice using some Mitee Bite clamps. Then I machined the majority of the shape using a 1/2 carbide Endmill with 3 flutes. I used a spot drill to spot the holes and then normal HSS drills to make the holes. Undersized the 4 alignment holes and used a .376 reamer to ream the holes just a bit bigger than the .375 dowel pins I am using to align the 2 halves of the mold. I could have pressed them in but I wanted to use Loctite to hold them in instead to avoid any burs or misalignment. I was worked pressing them in might cause a slight bur which would not let the mold faces close perfectly together. This would cause extra flash on the part.
I am not sure if this is the best way, but it is the way I am trying this time.
And this is what the first half looks like after machining it.
Then I flipped the part over and held it in my other Orange vise using a set of parallels. I then machined the back off
And this is what the first half looks like when it was done.
Then I checked to see if part matched the mold.
Then I repeated the process for the other half of the mold.
I still have to make a core but so far I think things are going well. The surface of the molds looks like it is textured or rough, but it really isnt. It is extremely flat, but you can still see the tool paths form the end mill. I might sand blast these molds to get a more uniform look. I want to first see if the molded part picks up the surface finish or not. I suspect it will. Then I can glass bead blast the molds and make some more parts to see the difference.
I also expect there to be some shrinkage of the part when molding. It is common to machine the mold slightly larger than the desired part. But I am not sure how much the material will shrink so I will just have to do some trial and error.
Another consideration is that my designed part is not tapered. Typically parts have a 1 degree taper to help them release from the mold. I don't have an endmill with a 1 degree right now. But I will order one and see if I can add a taper. Again, I want to try the part without the taper just to see what happens then add the taper and see the difference. One of the main reasons for this project is to learn more about injection molding.
Well that is all for this update. I am hoping to shoot the mold next week and will update again then.
He actually wants this part in a solid yellow color with a decal on the top. I will get back to that in a later post. But for now this is the shape I am going for.
I started out with modeling the part I wanted. Then I 3d printed a few so I could make sure my model was correct. I used that CAD model to design the injection mold. I am new to designing molds and there is a ton of details that go into making a good mold. But I learn best by doing things and making mistakes.
Then I go some left over aluminum from another project. It was thicker than I would have liked but its not a big deal to do a little extra machining. The mold is 6x5x1 in size and I started with this block which was 7x6x1.5
Next I machined the top side. I used a Haas Mini Mill 2 to do the machining. I held the material in a Orange vice using some Mitee Bite clamps. Then I machined the majority of the shape using a 1/2 carbide Endmill with 3 flutes. I used a spot drill to spot the holes and then normal HSS drills to make the holes. Undersized the 4 alignment holes and used a .376 reamer to ream the holes just a bit bigger than the .375 dowel pins I am using to align the 2 halves of the mold. I could have pressed them in but I wanted to use Loctite to hold them in instead to avoid any burs or misalignment. I was worked pressing them in might cause a slight bur which would not let the mold faces close perfectly together. This would cause extra flash on the part.
I am not sure if this is the best way, but it is the way I am trying this time.
And this is what the first half looks like after machining it.
Then I flipped the part over and held it in my other Orange vise using a set of parallels. I then machined the back off
And this is what the first half looks like when it was done.
Then I checked to see if part matched the mold.
Then I repeated the process for the other half of the mold.
I still have to make a core but so far I think things are going well. The surface of the molds looks like it is textured or rough, but it really isnt. It is extremely flat, but you can still see the tool paths form the end mill. I might sand blast these molds to get a more uniform look. I want to first see if the molded part picks up the surface finish or not. I suspect it will. Then I can glass bead blast the molds and make some more parts to see the difference.
I also expect there to be some shrinkage of the part when molding. It is common to machine the mold slightly larger than the desired part. But I am not sure how much the material will shrink so I will just have to do some trial and error.
Another consideration is that my designed part is not tapered. Typically parts have a 1 degree taper to help them release from the mold. I don't have an endmill with a 1 degree right now. But I will order one and see if I can add a taper. Again, I want to try the part without the taper just to see what happens then add the taper and see the difference. One of the main reasons for this project is to learn more about injection molding.
Well that is all for this update. I am hoping to shoot the mold next week and will update again then.
joberg
Legendary Member
Wow...that mold is a thing of beauty You're right on several points you're making about the molded part picking up the surface finish and the shrinkage of the piece. Glass blasting will be welcomed as the piece will be smooth and without issues.
It's going to be interesting to de-mold the part since you don't have a taper...but if the walls are all smooth, I wouldn't see an issue.
Eager to see your next update
You're right on several points you're making about the molded part picking up the surface finish and the shrinkage of the piece. Glass blasting will be welcomed as the piece will be smooth and without issues.It's going to be interesting to de-mold the part since you don't have a taper...but if the walls are all smooth, I wouldn't see an issue.
Eager to see your next update
I imagine there would be a huge demand for lightsaber chassis designs that would be in high demand. While 3D printing is great and all, I know that I would rather have a nicely made injection molded plastic chassis vs. 3D printed ones if the option were available.
The lens cover you made looks incredible!
The lens cover you made looks incredible!
drusselmeyer
Master Member
Do you use EDM in your tool and die making?
drusselmeyer
Master Member
I just saw this in another thread. The possibilities for mold making are immense.
We do use EDM sometimes but we don't have one in house so we have to sent that work out. It is a super cool tech, but sadly not one of the toys I get to play with myself.
drusselmeyer
Master Member
One of the things that does not get readily pursued here are the 1/4 scale /Studio scale vehicles in film. One of the stumbling blocks is the figures to go into them.
I had an idea to produce a set of bodies that could fill that void. Now that 1/4 scale male figures are readily available, albeit expensive, the only thing left that is not ready available are female action figure bodies.
For collectors; the gaps could be filled in their figure lines. For the builders, models could be completed by having figures occupy them.
For example: the power loader from Aliens was about 1/4 scale, but there is no Ripley figure for it, making any attempts to replicate one empty.
There is not even a suitable body to customize into Ripley. Yet, we have had a 1/4 scale xenomorph since 1979.
The Star Wars collection in 1/4 scale has had three companies producing figures and there is still no Leia nor any bodies to customize. So, no 1/4 scale speeder bikes.
I had an idea to produce generic bodies that can accommodate filling such gaps.
The main feature that would be needed is articulation -which means durable joints. These can only be produced currently by injection molding. Additive manufacturing is still not up to the task.
So, I suggest this a possibility.
I had an idea to produce a set of bodies that could fill that void. Now that 1/4 scale male figures are readily available, albeit expensive, the only thing left that is not ready available are female action figure bodies.
For collectors; the gaps could be filled in their figure lines. For the builders, models could be completed by having figures occupy them.
For example: the power loader from Aliens was about 1/4 scale, but there is no Ripley figure for it, making any attempts to replicate one empty.
There is not even a suitable body to customize into Ripley. Yet, we have had a 1/4 scale xenomorph since 1979.
The Star Wars collection in 1/4 scale has had three companies producing figures and there is still no Leia nor any bodies to customize. So, no 1/4 scale speeder bikes.
I had an idea to produce generic bodies that can accommodate filling such gaps.
The main feature that would be needed is articulation -which means durable joints. These can only be produced currently by injection molding. Additive manufacturing is still not up to the task.
So, I suggest this a possibility.
Do you already have CAD files for the parts you are interested in producing? Would you mind sharing them with me so I could take a look? How large are the parts in question?
This sounds interesting too. Do you know of any good sources for the CAD files?
A run of 100-200 is exactly what I was looking for. Most big shops wont touch a project this small, but its a good size for me to not get overwhelmed with either. I don't mind investing in a mold for a project like this. Do you have a link to where I can find more information about this project?
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