Dies are the hollow structures and important tools used for compression of tablets, lozenges and pills by using the compression machines in the pharmaceutical industries.
Role Of Dies
- The weight of the product being compressed depends on the dies.
- The powders or granules are filled in the die bore, then the weight is adjusted according to the formulation and is compressed by upper and lower punches.
- Lower punch remains inside the die bore from the lower side of the die to prevent product loss from the die bore.
MOC Of Dies
Different grades of steel are used as Material of construction (MOC) for the manufacturing of dies.
Commonly used steel grades are as follows,
Steel Grade A2
Steel Grade D3
Installation Of Dies
Dies are installed on the die table in the die housings by screws and when the turret rotates it results in rotation of the die table and dies as well.
What are Blank dies?
Blank dies, as the name indicates, are dummy dies that are not hollow and are used to block the die housing to prevent product loss.
When To Use Blank Dies
Blank dies are used in pharmaceutical industries in the following cases,
1.0 For Trial Purpose
To block the extra die housings if we want to use a limited number of punches for conducting some trials.
Sometimes we have to conduct a trial of the product and we have only a small quantity of powder or granules which are not sufficient to fill all the dies so we have to block the extra die housings to prevent product loss.
Suppose we have 300 grams of a powder product and we want to compress it on a 33 punch compression machine at 300 mg compression weight.
In this case, if we install all the dies and punches then the required results will not be achieved because our powder is not sufficient to uniformly fill all the dies so we can use only 5 or 7 dies and punches.
Suppose if we install 7 dies then the remaining 26 die housing will be empty and the product will fall through the die housing below the die table and be wasted.
We use blank dies in such circumstances to block the extra die housings to prevent product loss.
Common Practice/Conventional Practice
It is a common observation that in most of the pharmaceutical industries blank dies are not used rather a typical conventional die blocking practice is used which is as follow,
Operators install all 33 dies in the die housing and paste a tape on the upper and lower side of the die bore to prevent powder loss.
Some operators block the die bore with some material and then apply a piece of tape.
All these practices are not GMP compliant so try to use recommended blank dies.
2.0 Punch Damage
In the pharmaceutical industries, during routine tablet compression operation, the upper or lower punch tip may be damaged and we have to replace that defective punch with a new one.
Think for a while about what to do if we do not have an extra punch to replace?
Obviously we will remove the upper and lower punch and the die as well.
The reason for removing the die is that when we remove the lower punch the die bore will not be blocked from the lower side with the punch tip and product loss will occur.
After removing the die from the defective site we will install a dummy die or blank die at that place to prevent product loss.
In most of the Pharmaceutical industries,the die at the defective site is blocked by pasting a piece of adhesive tape on the upper and lower side of the die bore.
This practice is not GMP compliant and is also risky because if the tape is displaced during compression operation the product loss will occur.
Some operators insert a tablet inside the die bore then apply tape but it is also a risky practicetice so try to use a recommended dummy or blank die.
How to Get Blank Dies
Blank dies can be purchased from the vendors in the same manner as we purchase other compression toolings like routinely used punches and dies.
Blank dies can be purchased for both B type and D type compression machines.
- Stages and Mechanism of Tablet Compression.
- Advancements in tablet compression machines.
- Calculation of compression machine capacity.
- How to reduce compression machine breakdown.
- Direct compression method for tablets.
- History of compression machine.
- How to compress Bilayer tablets?