Collection: Pellet Press Dies - Circular

Video of Pellet Press Dies Assembly:

Powder Pelleting Die Set includes

• 1x Die Sleeve
• 1x Plunger rod
• 2x Spacers
• 1x Base plate 
• 1x Release ring with viewing slot

Machining and Material Selection for Our Pellet Press Dies

Each piece in our quality powder pellet press die sets are designed, machined and precision ground for simple, easy, reliable powder pressing. The carefully chosen steels for our powder press dies are heat treated for maximum hardness and strength, permitting reliable and repeatable long term performance. Our durable, hardened tool steel dry pellet pressing die sets can safely tolerate large stresses from the hydraulic press required to make quality pellets and the wide range of hydraulic pellet press and laboratory pellet press dies and in our selection range gives flexibility on the size of pellet you need. If you can’t find what you need – just let us know and we’ll make it for you!

Precision Powder Press Tools

Every one of our pellet dies are made to high tolerances to allow the pieces to slide together without allowing the powder to escape which would cause the die set to jam up and prevent it from working efficiently. The superior level of mirror surface finish of the interior pressing surface reduce friction and removeable spacers can be used reduce cross contamination between samples. Dies can be operated with or without spacers to give flexibility on thickness of pellets you want to make.

What Force Should you use with Your Pellet Die?

Check out the recommended maximum force for your die on the product page. For most pellets you do not need crazy high force (loads) to make good pellets. The force you can used is limited simply by the strength of the steel in the die set. In particular it is the plunger and the base plate which takes this load in the narrowest diameter (i.e. highest stress). If you use a strength approaching or exceeding the strength of the steel then this may lead to failure of your die. 

• Stay below the recommended loading on the product page
• Do not overfill you die sleeve with powder
• Make sure your press and die are aligned properly
• Always have a press guard in place
• Please do not test the limits of the steel. We have done this for you and provided the recommendations based on this data.

We recommend only loading the die to 50% of the yield strength of the steel. So if the yield strength of the steel is 80,000 psi, then you should only be loading to 40,000 psi. This is typically much higher than what you need to make a good pellet which would normally be in the range of 5,000-10,000 psi. 

Using super high forces to compress powders does not typically lead to better pellets, in fact, is can exceed the fracture strength of your compact. Leading to cracking in the pellet on release or "capping" where the top of the pellet comes apart from the rest. Once you get to a certain force, the compaction does not typically get much better.

The force from your hydraulic press is concentrated through the plunger deliver very high stresses. If you think about balance a few cars on the plunger which is narrower than your finger then get the picture. 

There are 2 main factors when considering these stresses in the plunger - 1 is the force divided by the cross sectional area of the plunger which is equivalent to the stress on your pellet. The other is the buckling stress and is related in part to the unsheathed plunger. So if you have a very large amount of powder and a lot of your plunger is outside of the die sleeve then this becomes an issue at elevated stresses. If this is the case, 1) reduce the amount of powder, 2) reduce the force used 3) use a long die sleeve height option or 4) contact us to make you an additional shorter plunger for use during pressing, then use the full length one for ejection.

If you are coming into the lab, you may not know the exact pressing history of the die you pick up, i.e. what forces which have been used on a die before you use it. Your pressure gauge may not be 100% accurate. If a plunger fails, is does so quickly with no warning, so please do not test the limits of the steel. We have done this and have lots of data on it.

If you need to press with a higher stresses then you can look at our low profile dies which are designed specifically for higher loading or we can custom make you a die with high yield strength stainless steel.

Pressing Long / Tall Pellets?

For many of our standard die sets you will see there is a longer die sleeve / plunger option of either 75 or 90 mm height. These are an option for our customers who are pressing long pellets or where they need for fill height for their powders. 

Please note - general pellet pressing convention is that the height (length) of a pellet should not greatly exceed the diameter. This is because the stresses in the compact are greater closer to the moving surface of the top plunger. So when pellets get significantly longer than the diameter, you can see cracking or other adverse effects. This rule is a general one and does not take into consideration all scenarios, however there is it for your consideration.

If you are pressing longer pellets, we suggest using lower forces, consider lubricating you die and consider using a small o-ring between your base plate and sleeve to allow some compression of your lower pressing surface udring pressing, to make the stresses more even through your compact.

If you are pressing longer pellets then you will have higher buckling stresses in your plunger under the same load as you have unsheathed plunger exposed during pressing. So, if you are approaching the recommended loading then reduce you force, reduce you pellet height or get a shorter plunger from us for use during pressing. These are available for purchase through the site up to a given size or you can contact us for a custom diameter / length.

Choosing the Right Hydraulic Laboratory Press for you Pellet Die Set

Once you know the diameter of the pellet you will be making you need to select the right hydraulic lab press to use with your die. Hydraulic lab presses come from the very small to the very large and you may just be stuck with what you have in the lab. If you have a choice, then this is what we suggest.

Make sure it has a force gauge. Using the right press with a correct loading and accurate gauge means you know what force you are using. This means safe pressing and better pellets.

Check the following things:

• Does it have a safety guard?
• Are the pressing surfaces flat? 
• Do you know what force is being applied or is the reading in pressure only?

Often cheap presses may not have a force gauge or may have a pressure gauge. If they have a pressure gauge this is not the pressure / stress in your die. It is the pressure of the oil in the under the hydraulic ram of the press cylinder (not your press). So in the manual there is usually a conversion to convert this pressure into a force. Which is the pressure divided by the effective surface area of the internal ram. You wont be able to guess what this is as it is hidden. So if you don't have this information, please get it before using the press - or better - can a different press!

What shapes can you make pellets in?

We make die sets for the following shapes:

1. Circular - this is the most common (using our standard dies, vacuum dies, low profile dies or custom dies)
2. Square / Rectangular (we stock a few sizes or make custom die sets
3. Ring Shapes (Annual Die Sets)
4. Custom dies for almost any profile shapes or curved surfaces

What can the pellets used for?

Our Pellet Press Dies are used across the works in universities, research centers, big pharmaceutical firms, small businesses and Fortune 500 companies. Whenever there's a powder which is required in solid form, you use a pellet die. So whether its a geological sample from the field, an electrode for a new type of battery, a sputtering target or a new material for a space rocket nozzel, it's going to get compressed into a solid pellet form for moving around, testing and analysis. 

At Pellet Press Die Sets, we offer the largest range of off the shelf pellet press dies and custom make dies on a daily basis for our happy customers. So if you have a project big or small and you need to make pellets - you're in good hands with us.

KBr Pellet Die Sets for FTIR  Analysis

Fourier-Transform Infrared Spectroscopy (FTIR) is a method of looking at the absorption of infrared light by a sample used to characterize new materials or identify and verify known and unknown samples. FTIR is sensitive technique which does not require much material. To make the sample for testing, a small amount of the powder to be investigated are typically ground and pressed with KBr powder in a pellet press die set which is transparent to IR radiation. Due to the small amount of material required, usually, smaller diameter dry powder press dies are used (3-10 mm inner diameter). Check out or standard die sets or consider our low profile dies which are a efficient way of making small diameter, thin pellets.

Custom Pellet Press Die Sets

If you don’t see the size you need or you want a custom rectangular dies, one of our square pressing dies in whatever size you need, or a heated pellet die, please fill out the custom die set form.