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A Case Study in Tablet Tooling Steel Quality

Natoli Engineering’s Metallurgy Department performs steel quality control on the tablet tooling that we send to our customers. However, they can also help to combat issues that put you behind in production. This analysis can help you troubleshoot tooling issues such as wear, breakage, corrosion, and fatigue.

So, when customers send us their tooling (regardless of who their supplier is), they trust Natoli to analyze it to help them make the best decisions on how to maximize its performance and its longevity. For example, they may be compressing a new, more abrasive formulation that could require more steel-resistant qualities. Or, they’d like to improve production yield, but need to ensure that they won’t sacrifice product quality.

We’ve combined our experience as the world’s premier manufacturer of tablet compression tooling with on-site metallurgical failure analysis. The result is the first and only focused resource dedicated to resolving failure and wear issues of metal parts.

The Situation

Recently, the Department had an opportunity to work with a high-profile customer that sells an over-the-counter nutraceutical product commonly found in stores around the country (if not the world). Nutraceuticals are well-known for having formulations that are more abrasive than the average pharmaceutical formulation, and as a result, compressing it requires a tablet tooling steel quality that is more wear-resistant.

Our customer was using D-2 steel in their punches. The question at hand was whether or not they should continue to use it, or switch to a super high-speed M-42 steel? D-2 is more durable, but a thicker punch cup land could mean reduced machine speed and product yield; vice versa for M-42. Natoli Metallurgy visually compared the abrasive wear of the two grades under a stereoscope.

D-2 is a cold work tool steel with high carbon and chromium contents. The high contents of
carbon and chrome give it high wear resistance. It is typically hardened to the range of 58-60 HRC.
M-42 is a super high-speed tool steel with moderately high carbon, high molybdenum and cobalt. It is a high speed tool steel that is typically hardened to 66-68 HRC.

To fully address the issue at hand, we needed a holistic approach. The solution wouldn’t be complete without looking at the challenge from four perspectives:

  •  Selection and treatment of steels to improve longevity of the tooling
  • Analysis of material chemistry and coatings
  • Troubleshooting tool failure in tool steels and stainless steels
  • Conducting wear testing on metal components

Figure 3 shows the area where the land should be on the D-2 sample upper punch. Figure 4 shows the punch tip edge where the land should be on the M-42 upper punch. In both images, the land is completely worn away.

A side-by-side comparison of two punch tips. The one on the left shows punch tip edge damage on D-2 steel. The image on the right shows punch tip damage on M-42 steel.
A side-by-side comparison of two punch tips. The one on the left shows punch tip edge damage on D-2 steel. The image on the right shows punch tip damage on M-42 steel.

The Result

D-2 performed slightly better and was more cost effective. M-42 showed signs of more severe wear. This could be explained by the slightly higher carbon content on the D-2 compared to M-42.
We advised our customer to continue to use the D-2 steel for their highly popular nutraceutical tablets. Natoli’s metallurgical analysis showed that the benefits of an increased yield from the M-42 steel was outweight by the risks of switching steel types.

Speed, Quality, and Cost in the choice of tablet tooling steel quality

While this story exhibits the metallurgical services we provided for this customer and others like them, there are some things that even we can’t overcome: the delicate balance of speed, quality, and cost in tablet development. It’s quite possible (and even recommended) that 2 of the 3 can be achieved, but harmonizing all 3 may be only theoretically possible.

In a more general sense, a product’s development can be made quickly, and in high quality, but it won’t be cheap to do so. Or, a company can produce a high-quality product while being cost-conscious, but it won’t be done quickly.

In the case of our customer, speed and quality were the most important, but only at the expense of the cost of tablet tooling. If they would have switched to M-42 steel, they would have had to replace their tooling more often (Speed? Check. Quality? Check. Cost? Nope.)

So, by reducing speed (the rate at which the tooling was used), our customer was able to focus on optimizing product quality and cost-effectiveness.

That’s why when you choose your tooling type, you must ask yourself which of these three are the most important to you: speed, cost, or quality?


For additional information on how our metallurgical services can help you refine your process, determine probable tool wear, and assess tool failure, contact us today or call us at 636.926.8900.

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I always say that the customer service is outstanding at Natoli and this is another example of the good work you all do there. Hopefully others know what a great team you all are at Natoli. Definitely my preferred supplier!

- Canadian Pharmaceutical Company