Artur Jakubiak explains how to get the right compression tooling
Contrary to its straightforward appearance, tablet compression is a very sophisticated, complicated and demanding process. Substantial static and dynamic forces run on punches and dies. Compression tooling actually turns out to be one of the most important and delicate elements of this process because its quality influences the produced tablets’ weight, hardness and appearance. Of equal important are the conditions the tooling is used in and the practice of using tooling in the correct way.
The Importance of Design
Performance of the compression tooling during the tablet compaction process depends on its correct design, which results in its ability to overcome the numerous process problems such as capping, picking and sticking, to name only the most common, but also to ensure the maximum tooling lifetime. Most of these problems could be avoided or at least limited already at the stage of the tablet design, but for the most of the applications we need to cope with existing tablets and established formulations. In such a case, no substantial modifications of tablet design are permissible. The changes mainly involve embossing parameters such as stroke angle, width and depths or slight corrections of the concave radiuses.
From this point of view, the only available way to influence the process and solve the problems remains tooling design. This includes the right choice of the construction material and enhancing the tooling performance by the correct heat treatment, applying coatings or special modifications such as rotating heads, etc.
5 Ways To Tailor Tooling
Tailoring tooling to the application is then one of the most important factors to make the compression process as much effective as possible. Therefore, the clear and precise requirements specification by the process owner is a crucial success factor.
Essential information needed for the correct tooling design could be divided in five main groups.
- The first is information about the tablet – usually tablet drawing or samples.
- The second is information about the tablet press – machine producer, machine model, number of stations and tooling standard (TSM or Euronorm).
- The third group is information about the tooling – tooling configuration (B or D with specification of the die size in case of B tooling – B, BB, BBB or BBS), material of construction and coating (if should be follow by the tooling supplier), specific requirements for surface roughness, dimensional tolerances and tip/die bore clearance (if it varies from common standard values), key angle (in case of shape or multitip tooling), dust groove standard (if needed), tooling marking (if different from tooling supplier standard), any other specific tooling modifications and the requested number of tooling including spares.
- The fourth is information about the compressed product – product properties (sticky, abrasive, corrosive), compression problems if occurred in the past (capping, picking, black spots, etc.), compression force needed (if it is known from previous experience).
- The fifth and final group is general information – meaning any specific documentation needed (if vary from standard measuring reports, material and coating certificates, delivery documentation).
Most of the compression tooling suppliers are assisting their customers with request for quote (RFQ forms), which assures the gathering complete information needed for fast and smooth and cost effective quotation, ordering, producing and tooling delivery proceess.
Artur Jakubiak is with Adamus