Contact Us Today 📱 +1-757-516-7358 📧 info@pelletpressdiesets.com

Cold Isostatic Presses (CIP)

We machine custom high pressure chambers for bench-top cold isostatic pressing (CIP). These chambers can be machined with cavities of from 1/2 inch to 3 inch diameter, and 1 inch to 10 inch long to withstand pressures up to 10,000. 20,000 or 50,000 psi.

Most industrial CIP systems are made for large pieces, they weigh thousands of pounds and cost $50,000-$200,000+. Our benchtop design precision made CIP for pressing lab-scale samples weigh 20-50lb and will cost you between $3000-10,000 depending on your requirements and specifications. For pressing odd / long shaped pellets in the lab and getting stronger "green" compacts- these are a game changer!

How To Get a PPDS CIP?

If you need a custom CIP please email info@pelletpressdiesets.com with the subject "CIP Inquiry". Please include the sample size you will be pressing and the maximum pressure to be used.

We have removed photos and drawing of what we make due to other companies trying to copy our designs - please contact us if you wish us to make you something or if you need more information.

An over-simplified schematic is shown here for conceptual understanding only

Cold Isostatic Press Schematic

Advantaged of Cold Isostatic Pressing:

  • Pressing from all sides
  • Denser compacts and pellets
  • Can press irregular shapes
  • Can press long aspect ratio cylinders

CIP materials

Our CIP dies are made with heat treated tool steel or high strength stainless steels. We design the chamber to fit your sample size.

High-Pressure Sealing

Our CIP chambers come with ultra high pressure sealing system to hold the high pressures and protect the O-ring sealant system.

CIP High Pressure Pumping System

All our CIPs are delivered with a pump to reach the desired pressure (max 50,000 psi). You do not need a hydraulic press to use our CIP.

We fit an appropriate precision pressure gauge to the outside of the chamber to you know what pressure you are applying

Cold Isostatic Pressing Description

Isostatic Pressing allows for pressing of long and irregularly shapes. The sample is placed within a "wetbag", typically a rubber or latex bag or mold (or even a simple latex glove) and pressure is exerted through a hydraulic fluid such as oil or water.

Uniaxial pressing (such as normal pellet pressing), as the name suggests only presses along one direct (axis). In isostatic pressing the sample is compressed from all sides equally. Because of this, the pressed sample is usually more stable after pressing and can reach higher density than uniaxial pressing.

Usually the sample is pre-molded e.g. into a disc form in a pellet press die, or a powder is put into a mold which gives it its shapes.

Examples of when CIP might be used in the lab

  • When you want to reach a higher density before sintering
  • When your pellet keeps falling apart before you can sinter it
  • When you have a long thin item
  • When pressing an irregular shape such as a donut or a shape which changing dimensions along its length

An example: A common use for our customers is when they want to press something long and thin. Such as a 5 mm diameter ceramic rod which is 100 mm long and would after be sintered. Using a  standard uniaxial die i) would not give good compaction along the length as it is so long, ii) would be very unstable after pressing and the iii) die sleeve might have to be 200 mm long. When adding the plunger on top, it would be unreasonably big for a standard press. 

If doing this with CIP, the powder could be filled into low cost latex tube of appropriate diameter, a simple knot or clip in each end, then place in the hydraulic fluid, the chamber is closed and the pressure applied to the fluid with the pump.

The pressure is held for a few minutes, then released. the chamber is then opened, the sample bag removed. Wipe the oil away from the outside of the bag then it can be opened (if reusable mold) or cut if low cost sacrificial mold like a balloon or latex tube and the sample is removed.

This sample now has been compacted from each side giving is more stability and uniformity and is ready for the next stages of processing.

There is less dimensional control with CIP than with uniaxial pressing. For instance using the example above, if you need exactly 5 mm diameter, then there would be some trial, error and calculations in your mold and filling procedure beforehand to get there. But once you are through that then it is a very repeatable process that offers some distinct advantages. Including being able to press very long aspect ratio pellets. Spark plugs are an example of a common item which are cold isostatically pressed on a industrial scale.

Cold Isostatic Pressing Wetbags and Molds

Cold Isostatic Pressing is also termed "wetbag" pressing, because the outside of the bag gets wetted by the pressing fluid. You will need a appropriate bag to press your sample but you have a lot of pretty easy and low cost options. Even thin flexible materials such as latex and rubber will stand up against very high pressures as they are not particularly highly stained (elongated) under this high pressure when pressed against something which does not elongate as much.

You can use anything from a latex balloon or lab glove to a custom latex mold for your pressing, what you need will depend on whether you are premoulding your shape into a compact before or whether you need the mold to provide the shape to your object.

Contact us if you have any questions about your mold options.