ram press Steel Ring and Plaster Die Design for RAM Press

[Mats]

Hi everyone,

 

I’m setting up a 100-ton RAM press for ceramic production and would really appreciate some advice on the overall process, the dimensions of steel die cases, and the plaster die design itself. Here’s what I’m trying to figure out:

 

Dimensions

How much larger should the steel rings be compared to the object being made? For example, I’m working on a small pot with a 12 cm (4.7”) diameter and a depth of 5 cm (2”). Is 3 cm (1.2”) of space between the cavity and the steel ring sufficient, or should it be larger? I’ve seen pictures with much larger distances—sometimes 10–20 cm (4–8”). Is that really necessary? It seems like a lot of wasted plaster if I can make the ring smaller. Also, is it better to make the case round or square?

 

Height of the Male Die Case Steel Ring

For the female die case in my pot example, I believe the steel ring height needs to be as follows: 

 

+ 5 cm (2”) plaster

+ 0.5 cm (0.2”) tubing

+ 2.5 cm (1”) plaster

+ 5 cm (2”) pot cavity 

= 13 cm (5.2”) in total

 

But how tall does the male die case need to be at minimum in this example? Would 2” + 0.2” + 1” = 3.2” suffice? And would this also apply to larger cases, say 60 cm (25”) in diameter? Or does the plaster need to be thicker to avoid cracking under pressure in larger die cases? Any formulas or general rules would be greatly appreciated.

 

Wall Thickness of the Steel

What wall thickness would you recommend for the steel rings to withstand the force of a 100-ton press without deforming?

 

Design Features

What’s the best and easiest way to secure the metal mesh for the air tubing? I’ve seen various methods: threading wire through small holes in the ring, using grooves on the inside of the ring to catch the mesh, securing it with bolts, or even using internal metal beams. Which method is the most reliable?

Also, some die case designs have bolts sticking out inside the ring so the plaster has something to grip and doesn’t slide out. How necessary is this feature?

 

Plaster Die Questions

When moving the two dies together in the press, what’s the ideal gap between the male and female dies at the sharp line where the clay is squeezed out (into the gutter)? What dimensions should the gutter have to effectively collect the clay and create good back pressure? How do these dimensions influence back pressure and the overall quality of the piece?

 

I’ve been surprised by how hard it is to find detailed explanations for all the steps in this process. If anyone has tips, book recommendations, videos, links, or personal experience to share, I’d be incredibly grateful!

 

To clarify, I’ve included two sketches illustrating how I believe the setup works in principle. However, what I’d like to know are the exact dimensions and the best way to approach the design of both the steel rings and the plaster die itself.

 

Thanks in advance!

 

Best,

Mats

Edited November 26 by Mats

[Hulk]

Hi Mats,
Welcome to the Forum!
Interesting project, looking forward to learning more about ram processing and design...

[Jeff Longtin]

Welcome to the Forum Mats. 

Not alot of people using 100 ton presses so you will need to engage in a little trial and error. RAM themselves used to hold classes for buyers of presses. Have you contacted them about online classes? 

I've made molds for a 30 ton presses. Mostly flat objects. Ring shape doesn't matter, steel thickness of 1/4" seemed to hold up just fine. 

Your suggestion for mold depth seems good. The metal mesh sits 1" above the mold surface and usually 2" above that was best.  (In other words, a mold about 3" in depth produced a durable mold, thinner molds, say 2.5" in depth, sometimes cracked after a few uses.)

In your diagram the surface of the bottom mold rises above the metal ring just a bit. In my experience, with a 30 ton press,, that would wear away pretty quickly. Best to keep both mold surfaces below the level of the metal rings. (That way metal rings are coming into contact with each other not cement surfaces.)

Good luck! Presses are amazing tools but also very challenging at times.

 

[Mats]

Thank you, both Jeff and Hulk!

 

I managed to get the press at a reasonable price, and since the pressure can be adjusted, I’m hopeful it will work. However, I’m not sure if RAM would offer an online course since I didn’t purchase the press from them.

 

Jeff, have I understood you correctly regarding the steel ring in the updated illustration?

 

I understand the gutter is a critical part of the die, but I’m unsure how to design it for optimal performance. Would it be possible to share some insights or dimensions for the details in the second close-up sketch?

 

a) If I’m correct, this acts as an additional outlet for clay if the gutter overflows but also influences back pressure(?). How narrow should the gap to the male die be when the press is closed?

 

b) How should the gutter be designed, and what dimensions are typically ideal?

 

c) I assume this detail is also significant. How wide should the gap to the male die be when closed? How narrow can the edge be? In my illustration, it looks rather fragile.

 

If it’s not too much trouble, a simple hand sketch with some dimensions would be incredibly helpful.

 

Once again, thank you so much for your help—it’s truly invaluable!

Edited November 29 by Mats

[Jeff Longtin]

The press molds I made were only for rubber die that were 1/4" deep max. As a result, the concept of a gutter is not something I'm familiar with. 

From my perspective I don't see the need for a gutter. When the two molds come together any excess clay comes squirting out. 

The questions you ask about clearances/widths is really just something you'll need to experiment with to find the best answer. (For your situation.) Sometimes I made molds that lasted for 100's of pressings and sometimes the molds broke/cracked on the first pressing. I presumed it was user error on the presser's part but perhaps it was an error on my part or the cement was inconsistent.

I do know a few folks who have presses and I'll see what they think. I'll post again when I know more.