Injection molding with new high temp resin


#41

That one says Van Dorn 170 HT Series. Does the 170 refer to tonnage? We also have a Van Dorn 270 HT as well as 6 other similar sized machines. I can get other models in the morning as I am off work now.


#42

The presses we have are as follows:

Van Dorn 170 HT Series
Van Dorn 230 HT Series
Toyo TM200 ES (we have 2 of these)
CLF-400T
JSW J500E-C5 (2 of these)

We have 2 others but they were being used and i couldn’t see make/model on them. @SchemeInc Any insight would be great as to how closely related these machines may be to yours, and how they might work with the Form 2 would be awesome. Our mold guy was here last night and said he is going to work with our CAD guy to create a mold. I guess it will be up to them as to which machine to use as its not my field. I look forward to hearing from you and about your tests later this week.


#43

Will do when we run. They aren’t my presses. I’m working with a partner injection molder. Additionally, the parts we run should have comparables from aluminum and/or P20 inserts that have already been produced… we will be replicating existing tooling for out trials, so we have proper parts to compare to.

I hope to have a couple of molding houses involved, so I’ll be sure to spec-out all aspects. Presuming the simple stuff pans out a viable, we will be including tools with ejector-pins, and inserts, so not just stupid-simple straight-pull, pick-out parts. We will start with the simplest, but work our way into the more complex.

In the end it’s a cost-benefit-time analysis. Given that a very capable shop can turn out a high-speed machined tool in, what, 72-hours? We’ll be looking for the sweet-spot, or time/complexity limit of this technology.

Insert size will be the first consideration… how long does it take to print the insert. From initial analysis, it’s looking like a 4x4 insert will be about the limit. Larger than that, if time is the driver, then high-speed machining catches up… but! There is likely a cost component that may make up for larger inserts. If the additive workflow can save enough cash, vs machining, then it has another marketplace… we will see!

It’s not like this hasn’t ben tried over the past 20-years. I’m just hoping that, with this new material, the part quality will be increased, insert cost will be decreased, and we find a nice home for additive tooling.


#44

Hi, I have been reading this thread with high interest and then it suddenly stopped at the point where it became interesting.
We are looking into using a form 2 for the development of our product. I am very curious to the results of the the high temp resin mold with industrial injection molding machines. Did it work?


#45

In my case we never ended up trying it! We never had the time/funds to put into this R&D project. So it would not go to waste we sold our high temp resin on these forums so it would not go to waste. I would still be interested in finding out if anyone else has tried it.

Also…for our purposes it just simply never seemed practical. We have produced many prototypes on the F2, several which we have moved to our mold maker to make 10s of thousands of the product. We honestly don’t have a need for scores to hundreds of prototypes.


#46

I may have some news soon. I’ll be printing a small single cavity mold to test this week.


#47

Here are the results of the high temp resin test I did.

Here’s a few things I learned that will make youe experiments easier:

  1. First, the clamp force holding the mold together is critical. On my machine the mold needs to be switched to horizontal with the spru sticking through the large flat side. (I have a hydraulic jack to clamp things together).
  2. I shimmed the mold inserts with tape. This allowed some flex and because the frame could give a little the cavity side cracked. Epoxy might help this along with a better clamp. (c-clamps aren’t ideal).
  3. You need to have a big thick gate to inject into the cavity with ABS. Polypropylene would be better and allow a smaller gate. Mine here was 1mm thick and seemed to be just OK.
  4. It works best to have some extra large venting to relieve internal pressure in the mold. Normally in a real mold the vents are 0.01mm tall. For this part I was at 0.25mm and that gave a place for the extra plastic to go when the mold was overfilled a little.
  5. The inserts will warp a bit after cure. Stick them through the frame a little bit to allow the clamping force to press everything tight. This is critical if you have holes in the center of the part.

This material will not over temp with ABS. It’s not even close to being an issue. I got the mold hot enough to keep the ABS nearly molten when I pulled the halves apart. This deformed the part but was an interesting test. The temp limit of the HT resin is well above the flow temp of ABS.


#48

Great info - thanks for posting.


#49

If your degassing the silicone you should still let it cure in a pressure chamber if you plan on doing your resin casting in the pressure chamber. This will make sure your part is accurate to the original since pressure chambers do change the mold properties.

Equally if you do a simple degassed mold no pressure your parts should be cast without a pressure chamber. Not a good idea to mix methods.


#50

I started to work a few weeks ago with the high temp resin. I am studying mechanical engineering at Mannheim University for Applied Science. My colleague and I are working on a project called: “Mold inserts by 3D-Print with the High Temp resin”. We are working with the Formlabs2 printer and a molding machine (Glöcker FX50R35, clamping force up to 500kN, injection pressure up to 1720bar) in our Institute of Production Engineering.

!

The last week we started some tests with our own created UV-cure box. We have checked the hardness of an untreated part, a UV treated part and a part with UV and temperature of 77°C.
We examined the flatness, angularity, drift of holes and measured all parts.
We printed our nozzle sided insert a few days ago. Unfortunately, we have not achieved the desired flatness on the top of the mold insert. The first printed layers of the insert are “slipped” and therefore not angular and dimensionally accurate. We used the default setting to align the part, but changed the point size (0.5mm), density (75%) and slope multiple (0.9). We want to print our ejection holes directly into the insert without reworking. This appears to be very difficult, because the holes are not in an angel of 90° to the surface. Do you have a suggestion on how to position the inserts to avoid these problems?
Position im Drucker


Next week we will be milling the carrier plates and probably drive first tests on the injection molding machine.


#51

Most of the resources I can find for running printed inserts are vague at best.

Most of the printed inserts that I’ve seen video of have been hand reamed to finish the ejector pin holes. There is normally some faceting to clean up from the STL file. If you want to eliminate this hand clean up I would recommend significantly increasing the STL mesh parameters.

I’ve also found that it is extremely hard to get the mold surface completely flat from the printer. I’ve ignored the flatness because we have enough clamp force to make the print flat. I shim the insert up to create interference during clamping. The part will go flat even with 100kN of clamp force. Only a very small interference is required.

Note: the mold insert must fit the mold shoe with a very close tolerance. Any gap between the insert and shoe will likely cause fracturing of the insert. You can fill any gaps with epoxy.


#52

Use a new build plate (since it will have no scratches) and print laying flat. The software will try to stop you, but it will print much better in that case.


#53

@Christian92

Dial-in the printer. A Search here for my name and step gauge should turn it up. I have a setup excel calculator on this site that will help you get to very accurate prints in x, y, and z. There’s a post here somewhere with all the files you’ll need. Hunt around.

As far as making an insert to fit into an aluminum or steel housing, why did you make it all a curved shape where the parts will need to mate? Much simpler and easier would be to make it rectangular with a standard radius at the corners. The standard radius would match the radius of the tool you used to mill the block. Actually, it would probably be a good idea to make the insert slightly larger on it’s outside, then machine it to precisely fit into the metal carrier mold block after it was printed and cured.

-C