Cold Isostatic Press (CIP)
We make 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 5 inch long to withstand pressures up to 10,000. 20,000 or 40,000 psi.
Our benchtop design precision made CIP for pressing lab-scale samples weigh 20-50lb and will cost you between $5000-10,000 depending on your requirements and specifications. Most industrial CIP systems are made for large pieces, they weigh thousands of pounds and cost $50,000-$200,000+. For pressing odd / long shaped pellets in the lab and getting stronger "green" compacts - these are a game changer!
How To Get a Benchtop CIP?
If you need a custom CIP please email firstname.lastname@example.org with the subject "CIP Inquiry". Please include the sample size you will be pressing and the maximum pressure to be used.
An simplified schematic is shown here for conceptual understanding only
CIP chambers available from Pellet Press Die Sets
Price includes chamber, high pressure pump, hose, space o-rings.
If you need a custom chamber size or addtional requirements please email us to let us know.
Advantaged of Cold Isostatic Pressing:
- Pressing from all sides
- Denser compacts and pellets
- Can press irregular shapes
- Can press long aspect ratio cylinders
Our CIP dies are made with heat treated tool steel. We can design the chamber to fit your sample size.
Our CIP chambers come with in house designed 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 40,000 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
What is Cold Isostatic Pressing Description
Cold Isostatic Pressing (CIP) is a process used to shape and compact powders into components of varying sizes and shapes. In wet bag cold isostatic pressing (CIP), the material is preformed then sealed in a flexible bag or mold. The bag is placed within a hydraulic fluid (e.g. oil or water) in a pressure vessel. Pressure is applied to the fluid, usually between 10,000 and 60,000 psi which is evenly distributed across the material. This method helps to reduce distortion, improve accuracy and reduce the risk of air entrapment and voids. It is widely used in the production of components for medical, aerospace and automotive applications.
What are the differences between Uniaxial pressing and Cold Isostatic Pressing
Both uniaxial pressing and CIP are methods for compacting powder samples. In uniaxial pressing a force is applied along 1 axis (i.e. up/down). It is used for pressing simple shapes which have 2 fixed dimensions (e.g. a cylinder or a square/rectangle. Uniaxial pressing requires a mold and a hydraulic press and it is a relatively inexpensive process. Some limitations of uniaxial pressing is that i) samples should have a relatively short aspect ratio i.e. should not be too long as they powder close to the moving pressing surfaces is compacted more than a long way away from the pressing surface and ii) samples can only have simple shapes.
In Cold Isostatic Pressing (CIP), the sample can either be preformed into a shape (e.g. using uniaxial pressing) or the sample can be placed in a flexible mould which can take almost any form. In both cases the sample is put into a flexible bag or mold and placed into a hydraulic fluid in a chamber. High pressure is applied to the liquid medium which in turn applies uniform pressure to the sample for all directions. This allows for a much higher degree of compaction than uniaxial pressing and thus can be used to produce large samples. The benefit of CIP is that it can produce complex samples with uniform density and shape. The limitation of CIP is that it can be a more expensive process than uniaxial pressing… until now, with the new benchtop CIP from Pellet Press Die Sets.
5 key advantages of Cold isostatic pressing versus uniaxial pressing
- More uniform product properties, greater homogeneity and more precise control of the finished product dimensions
- Greater flexibility in the shape and size of the finished product
- Longer aspect ratios possible (i.e. long thin pellets)
- Improved compaction of the powder, leading to improved densification
- Ability to process materials with different characteristics and shapes
- Reduced cycle times and improved productivity
Key advantages of benchtop CIP in laboratory setting:
- Reduced cost
- Faster loading and unloading
- Larger chamber diameter compared to piston style whilst being 5 times lighter no additional big heavy press required
- Reduced maintenance with longer O-ring life as using a static O-ring rather than dynamic o-ring getting destroyed over sliding motion
- More space in the lab and easy to move between labs if required
- Easy to operate
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 large aspect ratio i.e. 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 at email@example.com if you have any questions about your mold options.
Standard operating procedure for the benchtop cold isostatic press
- Before you start it is handy to have some paper towels available to wipe up any drops of oil. Place some clean paper dowel down where you are working to provide a clean workspace.
- Verify that the Cold Isostatic Press (CIP) is in proper working order before beginning a pressing cycle, including the o-ring is in good condition
- Prepare parts to be pressed. Make sure all parts are clean and dry.
- Place the parts in the rubber bag and remove excess air using a vacuum pump and seal. Put the bag into the oil in the chamber.
- Check oil is up the correct level and close the CIP
- Press up to the desired pressure (up to 40,000 psi)
- Hold at desired pressure for 30s to 5 mins. As the sample reduces in size, it is usually to see a small decrease in pressure. If a large drop is observed, please stop and check o-ring and correct assembly before restarting.
- Once the pressing cycle is complete, open the valve on the pump to release pressure, allow pressure reach zero, open CIP and retrieve sample/s
- Remove the parts from the oil, dry off excess oil and cut open, keeping oil away from the sample. Inspect the parts for any defects or irregularities.
- Wipe down the Cold Isostatic Press, check O-ring and store ready for next use.