Tablet compression machine tooling consists of upper punches, lower punches & dies. The number of punches & dies varies depending on the type & model of tablet compression machines. The compression machine tooling is used to convert the powder or granules into tablets. The size, shape, embossing & weight of tablets depend on the tooling used for the compression machine.
The conventional tooling used in pharma is known as single-tip tooling, as the punch consists of only one tip to compress the tablet & die has only one cavity/hole to fill the powder or granules for compression.
The new emerging concept for tablet compression machine tooling is multiple tooling. There are many benefits & constraints associated with multi-tip tooling, which will be discussed in this article, but first, we will learn what multi-tip tooling is.
Multi Tip Tooling
As the name indicates, in multi-tip tooling, each punch has more than one tip to compress the tablets & each die has more than one cavity to fill the powder or granules. The number of die cavities will be the same as the number of tips & number of tips may be 2,3,4,5, or more, depending on the punch size & tablet dimensions.
Why Use Multi-tip Tooling?
The main aim of replacing single-tip tooling with multi-tip tooling is to enhance the output or productivity of the compression machine, but how? Let’s try to understand with a practical example
For Single-tip Tooling
Suppose we have a double-feed tablet compression machine having 35 stations. The tablet production capacity of this machine can be calculated by using the following formula
- Number of stations × rpm × 2 × 60
The number of stations is 35
rpm = speed or revolutions per minute, & suppose in our case it is 30.
2 = Feeding system
60 = for per hour output
Add values in the formula
- Number of stations × rpm × 2 × 60
35 × 30 × 2 × 60 = 126000 tablets per hour.
For Multi-tip Tooling
Suppose we have the same compression machine which was used above with the same specifications, but the tooling used has 3 tips, meaning 3 tablets will be compressed by one punch at a time.
The capacity of this machine using multi-tip tooling will be calculated by using the following formula.
- Number of stations × rpm × 2 × (No of tips) × 60
The number of stations is 35
rpm = speed or revolutions per minute, & suppose in our case it is 30.
2 = Feeding system
No of tips = 3
60 = for per hour output
Add values in the formula
- Number of stations × rpm × 2 × (no of tips) × 60
35 × 30 × 2 × 3 × 60 = 378000 tablets per hour.
Benefits Of Multi Tip Tooling
The main benefits of multi-tip tooling are,
- Enhanced Productivity
- Operation Cost
Enhanced Productivity
The output of the compression machine is increased by the installation of multi-tip tooling, as we can compress more tablets as compared to single-tip tooling.
Operation Cost
The cost of operation is reduced due to less compression time.
Constraints For Multi-Tip Tooling
The main constraint for multi-tip tooling is measurement of compression force for individual tablets.In fast speed tablet compression machines the tablet rejection system works based on compression force means if tablet thickness & compression force is kept constant the change in compression force will be due to the die filling i.e weight of tablet.
If force is increased, it means weight is increased and vice versa.
The maximum and minimum weight ranges are adjusted by measuring the compression force during normal operation. If any tablet goes above & below the range, it is rejected by the auto rejection system and is collected through the rejection chute.
In single-tip tooling, the compression force by each punch is applied over a single tablet & recorded individually during the compression process & rejected tablets can easily be detected due to variation of applied force.
In multi-tip tooling, only the overall force applied by the punch can be measured & there is no record about how much force is applied on individual tablets.
Suppose we have a 7 mm multi-tip tooling having 3 tips. For single tip tablet compression the force of 10KP is required for one tablet and in case of 3 tips the over all force of 30 KP will be measured by the machine and due to the lack of system available to measure individual tablet force the measurement of weight variation of tablets bases on compression force will not be possible.
So, in multi-tip tooling, the over and under-weight tablets can not be rejected precisely.
Speed Reduction
The second constraint is regarding the tablet press speed. It is generally observed that a higher compression force is required for multi-tip tooling as compared to single-tip tooling. To achieve higher pressure, usually we have to reduce the speed & ultimately the speed reduction results in low productivity.
Due to slow speed, the benefits to be achieved by multi-tip tooling are overlooked.
Cost
The multi-tip tooling cost is high compared to the single-tip tooling, so the cost overrides the time saving or productivity enhancement.
Machine Condition
Many old-fashioned or specific models of the tablet compression machines do not have the ability to exert high pressure for multi-tip tooling.
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