Andy Dumelow is PharmaCare manager at I Holland.

Andy Dumelow

With millions of tablets coming off production lines daily, it is no surprise that tooling can be affected. Consistent compaction of granules into a quality solid dose form is challenging enough for manufacturers without the added concern of the tooling not being up to the job.

The condition of punches and dies will have a substantial impact on productivity, so it is crucial that all tablet tooling is optimized through simple maintenance procedures to enhance performance and improve longevity.


Don’t Gamble on Tablet Tooling Maintenance

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Andy Dumelow is head of Technical Sales at I Holland.

When referring to this article, please cite it as A. Dumelow, “Don’t Gamble on Tablet Tooling Maintenance,” 

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By following some fundamental steps, manufacturers can optimize their tablet tooling maintenance and resulting productivity.

Don’t Gamble on Tablet Tooling Maintenance

	Cleaning for tablet press tooling is essential within pharmaceutical manufacturing. It is vital to remove any contaminants from punches and dies to prevent cross-contamination during tablet compression. Cleaning should be the first step in a planned maintenance and audit program. Based on this understanding, ultrasonic cleaning has been developed to clean tablet tooling products efficiently and to a high standard.

	Ultrasound transducers create microscopic bubbles that provide a soft, yet comprehensive cleaning action, eliminating the need for abrasive cleaning. Ultrasonic cleaning is therefore highly effective at cleaning the fine and delicate details of tablet compression tooling in and around embossing, for example.

	Traditionally, tool cleaning is often carried out manually using brushes, and alcohol. This is a time consuming method, however, and is often ineffective at removing contaminants that have adhered to areas such as embossing on the tip face, keyways, and seal grooves, which make the contaminants difficult to reach and remove. With manual cleaning methods, effectiveness often varies from technician to technician depending on how skilled they are.


	Using a precise and detailed cleaning method, such as ultrasonic cleaning, provides the most reliable method to remove any contaminants. Ultrasonic cleaning can deliver an extremely clean surface within a few minutes with a cleaning process that is repeatable, unlike the manual techniques identified previously.

	During the ultrasonic cleaning process, a technician will load the punches and dies into a stainless-steel basket ready for cleaning, which is then submerged into an ultrasonic cleaning tank. Ultrasonic cleaning units contain a converting transducer that produces sonic frequencies approaching 40,000 cycles per second that create millions of microscopic vacuum bubbles. These then implode when they make contact with a surface and therefore remove all dirt and other contaminants including toxic chemicals.


	This cleaning is a result of the release of energy caused by the production and collapse-otherwise known as cavitation-of the microscopic vacuum bubbles. This energy release results in sound waves that reach, break up, and lift off all of the dirt, residue, and other contaminants, which are then removed from the machined face, before being carried away as a suspended particle.

	Certain parts, typically tablet punches require a more thorough clean to avoid quickly clogging up with contamination. This application enables pharmaceutical manufacturers to extend the time between scheduled routine maintenance for machinery parts and as a result, improve productivity and lower labor costs.


	There are preferred conditions to operate in when performing an ultrasonic clean on tablet compression tooling. “With the units we supply, we recommend cleaning tablet tooling for 10 minutes at 50 °C,” says Andy Dumelow, PharmaCare product and market manager at I Holland.

	As steel is the primary component, “the units must contain a detergent designed for use in an ultrasonic cleaner and for cleaning steel components,” he goes on to say. “Also, because the majority of tablet tooling is not stainless steel, a corrosion inhibitor must be used.”


	While cleaning is one of the most important parts of a tooling maintenance program, it only makes up part of the overall process. Cleaning should, therefore, form only the first step in maximizing efficiency and achieving optimum productivity within tableting equipment.

	Once the cleaning process has been completed, the tooling should then undergo a thorough and comprehensive full maintenance process to ensure punches and dies are maintained and stored correctly.


	Adopting a robust tooling maintenance process is essential to help eliminate a key number of tablet manufacturing problems and tablet tooling failures. I Holland’s PharmaCare 7 Step Process is a logical, planned, and professional approach to tooling maintenance, measuring, and storage that has been adopted by many companies as a standard operating procedure.

 Clean. This is the most critical step (along with Step 5: Polish) as punch and die cleaning delivers noticeable benefits during production, reduces tablet press downtime, and helps to increase productivity. Cleaning is vital to remove problematic residue to avoid product contamination and potential production issues, such as sticking and picking, caused by old product adhering to the surface of the punch tip.

 Assess. Punches and dies need to be visually and regularly inspected. Once the tooling equipment has been cleaned and dried, it should then be carefully assessed, using the same microscopic precision that ultrasonic cleaning provides. Tooling should, therefore, be inspected under magnification to observe and identify any defects that can create tableting issues and disrupt performance.

	This habit identifies whether any tooling maintenance is required. Identifying damage off the tablet press, at this stage, is far less expensive and time-consuming. High magnification lenses and microscopes, providing precision and clear high-quality imagery, should be used to display any signs of damage, wear, or corrosion, and to validate the cleaning process.

 Repair. If tooling has experienced light surface wear, corrosion, and minor damage, then this can be repaired and re-worked to a useable condition. It is imperative that this repair is carried out, because worn tips can result in poor quality tablets and inferior embossing definition, which can lead to picking and sticking. Equipment including a motorized chuck and double-ended polishing motors are used in conjunction with abrasive polishing accessories. Repair should not be carried out on any coated tooling, because this may remove the coating from the punch. The repair should be carried out by well-trained and experienced maintenance technicians to ensure that the tooling does not exceed tolerance limits.

Measure. Measuring is essential after repair to ensure that critical tooling dimensions have been maintained within an acceptable working tolerance. The equipment required for measuring can range from simple hand-held micrometers, vernier callipers, and height gauges to semi-automatic, computerized digital gauging systems.

	Measuring should be carried out at regular intervals to check for natural wear during the compaction process. The essential measurement is the critical working length of the punch, as this controls tablet thickness, weight, and ultimately, dosage.

	Following the previous steps in the process, the measurement of the critical working length ensures that the punches are within an acceptable tolerance range for good tablet weight and thickness control. It also means that this measurement or other data are not affected by outside influences, such as oil or compacted granule.

 Polish. Automated polishing will maximize efficient and effective tablet production by helping to keep tooling in optimum condition. By following this process and correct maintenance, costly tablet press downtime and compression problems associated with capping, tablet weight, and thickness variation can also be reduced.

	Automated polishing is essential to ensure punches are evenly polished to a consistent finish. Automated polishing ensures optimum and consistent tooling condition for maximum productivity, reduced sticking, and saved labor costs in terms of time spent on polishing.

	The automated drag polishing system offers a more controlled and consistent process, which does not rely on on the skill and experience of the operator. This also allows for up to 85 punches to be polished in one 20-minute cycle, providing efficiency gains. Re-cleaning after polishing is not required provided that a food-grade polishing media and paste is used during this operation.

 Lubricate. Lubrication is important to protect, preserve, and aid smooth tooling operation in the press. A range of oils and greases can be recommended for different applications such as preservatives or for lubrication purposes. A non-toxic, FDA-compliant oil or grease is recommended for this step.

	In addition, a product that offers machine component protection and lubrication performance with a wide temperature range is sought to ensure it is appropriate for use in all machines.

 Store. Tooling storage and transportation should be purposefully designed and developed to maximize security and safe handling to minimize damage and deterioration. There are a variety of products available to store tablet tooling safely and securely including custom-built storage cabinets and storage containers.

	It is imperative that the tooling itself is separated to avoid contact and to ensure that the tooling condition does not deteriorate during storage. Due to the nature and weight of tablet tooling, storage should also ensure safe handling for operators, and therefore, tools should only be handled when necessary. 


	The application of the seven-step process may have a direct impact on the reduction of many common tablet and tooling problems, resulting in a better quality end product, which can provide direct cost savings to the tablet manufacturer. The PharmaCare 7 Step Process, developed by I Holland, follows years of research and experience in tablet tooling manufacture. It has been designed to help users extract the maximum life from tablet tooling through a consistent approach to tooling maintenance that supports production. 

A seven-step process may reduce many common tablet and tooling problems, resulting in a better quality end product.

Maximize Efficiency in Tooling Maintenance

We have talked previously about the importance to maintaining a logical, planned, and professional approach to tooling maintenance and storage to ensure tablet tooling failures are avoided. 

 of the recommend PharmaCare seven-step process is the most critical part of the program. Punch and die cleaning is essential for the removal of residue to avoid product contamination and potential production issues, such as sticking and picking, caused by old product adhering to the surface of the punch tip. 

A good cleaning regime goes hand in hand with a good polishing regime, which forms Step 5 of the process and is arguably the next most critical step. It is cleaning and polishing that deliver most noticeable benefit into production, reducing tablet press down time and helping to increase productivity.

Automated polishing is an integral part of this seven-step process and will maximize trouble-free tablet production by helping to keep tooling in optimum condition. By following this process and correct maintenance, costly tablet press downtime and compression problems associated with capping, tablet weight and thickness variation can also be reduced.

With today’s modern tooling often being supplied with coatings, automated polishing is essential to ensure punches are evenly polished to a consistent finish so these coatings are not removed prematurely. Automated polishing ensures optimum and consistent tooling condition for maximum productivity, reduced sticking, and saved labor costs in terms of time spent on polishing.

Manual polishing using polishing pastes with a motorized chuck or double ended motor may be considered as remedial action. However, this is an abrasive polishing method and care must be taken not to deform the tip profile and embossing causing a deviation from the tablet specification. Extensive polishing of die bores is not recommended as this can easily alter the size and geometry of the bore leading to ejection problems and incorrect tablet size, weight, and thickness. Only light polishing or cleaning should be undertaken manually. Polishing should result in a mirror finish and smooth tooling surface. Due to the controlled and repeatable process, adoption of an automated polishing regime would always be preferable as all punches are polished to an even finish.

Remedial manual polishing can be conducted using double ended polishing motors with nylon polishing wheels and fine abrasive compounds. A more controlled and consistent process is the automated drag polishing system, which relies less on the skill and experience of the operator. This also allows for up to 85 punches to be polished in one 20-minute cycle, providing efficiency gains. Re-cleaning after polishing is not required provided that a food grade polishing media and paste is used during this operation.

 One method of polishing is to use the new I Holland MF80 automated punch and die polishing machine. With a 80-litre media drum and punch holders, giving a maximum of 85 B or 60 D punches per polishing cycle, it is an important part of this critical fifth step in the PharmaCare seven-step process.

Seven Steps to Solving Tabletting and Tooling Problems---Step 5: Polish

The PharmaCare seven-step process is a logical, planned, and professional approach to tooling maintenance, measuring, and storage that has been adopted by many companies as a standard operating procedure. Over the last three weeks, we have been looking at each step and the benefit of adopting the process. This week, we look at Step 4, Measure.


  Measuring is essential after repair to ensure that critical tooling dimensions have been maintained within an acceptable working tolerance. The equipment for measuring can range from simple hand-held micrometers, vernier callipers, and height gauges, to semi-automatic, computerized digital gauging systems. One such tool is the Holland Die Condition Monitor (HDCM), which can measure  the condition of die bores, ensuring that optimum life is achieved from the dies to prevent the production of damaged tablets. Die bore wear, or ‘ringing,’ is a common defect that can lead to problems, such as tablet ‘capping’ and tablet ejection issues, which result in wasted product and reduced tablet output. Ringing is caused by abrasive wear and deformation from continuous forces acting on the face of the die bore. This is accelerated when compressing hard and abrasive granules found in some formulations, particularly vitamins and minerals. This wear can be identified using visual assessment, but precise equipment should be used to measure and monitor this wear. This physical die condition monitoring can result in early diagnosis before the defect has a negative effect on tablet output.
  Measuring should be carried out at regular intervals (even if repair has not been necessary) to check for natural wear during the compaction process. The essential measurement is the critical working length of the punch, as this controls tablet thickness, weight, and ultimately, dosage. The control of tablet weight and thickness is important as these parameters influence the thickness of the tablet ingredients, and one of the most common causes of tablet weight/thickness variation is inconsistent punch lengths. The critical working length of the punch can be easily measured and monitored to ensure consistency across the tool set. Any slight variations from the tolerance range can be addressed using the repair equipment to bring the lengths into range.

By following the previous steps in the process, including 

, measurement of the critical working length during Step 4

ensures that the punches are within an acceptable tolerance range for good tablet weight and thickness control. Importantly, as the punches are already clean and assessed, outside influences to measurement, such as oil or compacted granule on the punch tip face, will not interfere with measurement data.

Over the last three weeks, we have been looking at each step and the benefit of adopting the process. This week, we look at Step 4, Measure.

Seven Steps to Solving Tabletting and Tooling Problems---Step 4: Measure

Carrying on from our weekly column to help you eliminate a number of tablet manufacturing problems and tablet tooling failures with a simple seven-step tool-care process, we look at the third step, 

. This is part of I Holland’s PharmaCare seven-step process for tooling maintenance.

Light surface wear, corrosion, and minor damage on tooling can be repaired and re-worked to a useable condition. Worn tips can result in poor quality tablets and inferior embossing definition, this can lead to picking and sticking. Equipment such as a motorized chuck and double ended polishing motors are used in conjunction with abrasive polishing accessories. Repair should be carried out by well-trained and experienced maintenance technicians to ensure that the tooling does not exceed tolerance limits. Repair should not be carried out on any coated tooling as this may remove the coating from the punch.

If the damage is only slight, it may be possible to use Step 3 to repair the damage, removing any burrs and re-working the tip edges to a good useable condition, ensuring consistent tablet appearance. If it is found that there is head wear to the punches and for example the head ‘dwell’ flat, which is in contact with the pre-compression and main compression rollers, any light wear can be removed using mildly abrasive materials followed by remedial polishing through Step 3. This should then be followed by measurement of the critical working length during the measurement stage, Step 4, which we will discuss next time.

When in a new condition, the surfaces of tablet punch faces are usually polished to a high mirror finish; however, these can deteriorate over a period of time due to the continuous compaction of granules. This deterioration can lead to tabletting defects such as ‘picking’ and ‘sticking’ brought about by adhesion of the product to the now rough finish. This deterioration can be identified during assessment (

), the granule can then be cleaned off with an efficient cleaning system (

), and the finish can be improved or repaired by using a remedial polishing process and finished using the automatic polishing method to be outlined in Step 5. Any repair work should be followed by Step 4: Measuring, which is essential after repair to ensure that critical tooling dimensions have been maintained within an acceptable working tolerance. We will look at this in the next issue.

Carrying on from our weekly column to help you eliminate a number of tablet manufacturing problems and tablet tooling failures with a simple seven-step tool-care process, we look at the third step, Repair.