Mold Weight Capacity

[donguinesj]

Hi everyone, I'm new on this forum and hoping to get some help. I'm still new to injection molding and hopefully I can get some advice from the more experienced members/moderators.

We're planning to mount a mold with a weight of 2,050 kg (Moving Half = 1,050 kg; Fixed Half = 1,000 kg) to a 175 Ton machine, Klockner-Ferromatik FM175 to be specific. Is the machine capable of carrying such weight? Sorry I can't find the mold weight capacity on the machine specifications.

Thanks in advance!

[MTUHusky]

Hello and Welcome to the Forums!

The machine should have no problem carrying the weight. The questions you need to answer are:

- Can the mold dimensions fit in the machine? The tie bars are going to be your limiting factor here. If your tie bars are 1.25ft x 1.25ft apart and your mold is 1.5ft x 1.5ft then your not going to fit!
- Does the machine have enough shot size capacity in the barrel to fill the mold and pack it out?
- Does the machine have the pressure available to fill the mold? i.e. is it going to take 30,000 psi to fill the mold but your machine is only capable of 25,000 psi. Don't forget to convert hydraulic to plastic pressure!
- With the mold installed, is there enough "open" distance to eject the part and runner when the mold is fully opened? If your are using automation then you need to add the size of the robot arm in there too!

Hope this helps!

Husky

[MTUHusky]

I just wanted to add the specs for your machine:

The distance between tie bars: 520mm x 520mm. Your mold needs to be smaller than these numbers.


Maximum daylight (or Maximum distance between the platens): 1000mm, Take the width of your mold + length to open the mold so part and runner can come out + ejection stroke + room for robot arm (if needed); all should be less than daylight. So if your mold is 500mm wide and you need to open it 200mm to get the part and runner out and the ejectors stick out 50mm and your robot arm is 150mm, then you have 900mm with 100mm of clearance; you would be good.

Shot Volume: 510 cm^3, your shot volume for the mold in question cannot be greater than this number. When calculating this number you need to use melt density, not solid density. Also keep in mind that I got these numbers from a used machine someone was selling. They may have changed the barrel and screw to a different size. If so your numbers for the shot volume would be different.

Husky

[chrisprocess]

Machine should be capable of carrying such weight but you may need to look into additional support legs if the manufacturer recommends it.

Machine will run much smoother and your equipment will last longer

[donguinesj]

Hi Husky and chrisprocess. Thanks a lot for giving your comments into my concern. Great help!

Just one more thing, the mold we're going to mount exceeds the vertical (length) of the platen by 23 mm per side (top and bottom). The mold maker have reassured me that this would be fine and I too think that this would be OK since I think that the part that exceeds is still within the range (area) of the clamping force which means no worries regarding possible flashing on the upper and bottom cavities. The product area is also within the platen area. The platen size is 820x820 mm; tie bar distance is 520x520 mm; and the mold size is 510x866 mm.

Could you share your opinion regarding this condition? Are there possible risks with this or should I be confident that everything will be fine?

Thanks a lot!

[chrisprocess]

How does the machine deliver the clamp pressure? Center of platen or the edges?

[MTUHusky]

As long as your part detail is within the platen limits then you should be fine and shouldn't see any mold flexing. Just check that the 23mm hanging over the edge isn't going to crash into anything else (robots, de-gaters, mtc equipment, etc...). If the mold does flex a little and you find yourself with flash on the outside cavities and shorts on the inside cavities (or vise versa) then you can try limiting the flex by lowering your pressures. You can lower your pressures by decreasing fill speed and/or increasing melt temperature.

[chrisprocess]

You should be fine though just make sure you've got enough clamp pressure for your parts!
And contact the machine manufacturer to be sure.

[donguinesj]

Hi guys, thanks a lot for sharing your ideas and for giving suggestions. Appreciate it a lot!