To ensure delivery of our emails to your inbox, please add to your address book.
Tablets & Capsules SDD
Flashing during tablet compression, part 3
Q: What causes protrusions around the edge of tablets after compression, and how can I prevent this from occurring?
imageA: Mike Beyl, Wilson Tool International, says:
In part 1 of this series, I explained that the protrusions that form along the tablet band during compression are called flashing, discussed flashing's impacts and causes, and recommended investing in a setting tool that can reduce tablet-press setup time and achieve a more consistent alignment of the upper punch in the die bore. In part 2, I discussed how properly designed tablets and tools can reduce excess pressure and wear that leads to more clearance and flashing. In this third installment of the series, I'll discuss how good tool-handling and maintenance methods can reduce flashing.
First, be sure to include standard, periodic, preventive maintenance (PM) schedules in your standard operating procedures (SOPs), optimized for the type of product or products that the tools affect. To start, review your SOPs for maintaining tools with a tooling supplier. Tooling suppliers are the best source for tips to extend tool life. I would also recommend that you involve your alternate supplier in this process to gain a different perspective.
Dents or dings are major contributors to premature punch-tip wear and failure, and improper handling is their most common cause. Tablet tooling is made from hardened steel, but punch tips are very delicate and easy to damage if they impact another punch or fall on an unprotected floor. The area of highest concern is the land around the perimeter of the punch cup, which is the part of the tool that tends to wear out first and that tends to take the most abuse during handling.
Good handling is crucial not only to the life of the tool but also to the proper functioning of the tablet press. A damaged tool can damage the press during operation, which can then impact the next set of tooling, causing a quickly increasing cycle of damage.
Tool handling
Companies often blame tool damage during handling on clumsiness or inattention, but proper tool handling procedures can go a long way toward preventing damage from occurring. Minimizing handling steps will protect your tools. Examine a tool's life-cycle and write down each step that requires handling:
  • Decide which tasks you can complete together. For example, do you remove a tool from a tote to perform a visual inspection, put it back in the tote, and then repeat the process to measure working length? Could you remove a handling step by staging these tasks together?
  • Determine if you can eliminate tasks. For example, do you transfer tools from a cart to a cleaning rack? Could the cleaning rack be a part of the cart that lifts off?
  • Establish how often you really need to polish, measure, and inspect tools. Formulations can vary regarding abrasiveness and stickiness. Consider optimizing your schedules based on your drug product's needs.
Evaluate your methods of storage and transport in trays, bins, totes, tables, carts, and racks and redesign them to reduce damage to tools:
  • Decide if damage to tools occurs during transport and storage. Can you change your methods so that tools don't come into contact with one another during those processes?
  • Determine if movement during transport causes damage. Do you secure your tools during transport?
  • Evaluate the weight of the tools during transport. Is the transport weight excessive?
  • Determine if tools are easy to reach for a given task. Are you attempting to save floor space by making drawers or shelving too low or too high? Doing so can increase risk to operators, slow process times, and raise the chance of a tool mishap.
  • Decide if tools placed loosely on tables or carts are free to roll off an edge. Does the table or cart have an edge barrier? Does the workspace have a floor mat to cushion a tool's fall in high-risk areas?
Assess your methods of cleaning, measurement, repair, and press setup to decrease damage to tools:
  • Determine if personnel remove multiple tools at a time from storage or transfer totes. If so, does the employee hold more than one tool in his or her hand simultaneously? Best practice is to handle just one punch at a time.
  • Ascertain if multiple tools have the opportunity to touch one another during washing. Do you place a handful of tools loose in a bucket?
Tool maintenance
imageYou must maintain the sharpness of the land outside edge to minimize flashing (photo).
Buffing the punch tip can round the land outside edge. While buffers are very common in tool rooms and are quick to use, they can affect tablet quality when used to polish a punch cup. Instead, consider using a hand-held, variable-speed rotary tool with a small brush (photo). Also, tool manufacturers typically use a stereo
imagezoom microscope to efficiently inspect tools, and I recommend investing in one for your tool room as well. This microscope allows the tool maintenance person to quickly identify uneven wear, cracks, and excess material left in an engraving after cleaning as well as hard-to-see changes that may be occurring in the land or other parts of the punch tip. A loop can do this as well but isn't as efficient or as effective at spotting small details that can lead to big problems later.
imageAfter cleaning, you should repair and polish the punches if needed. If you find that the punch land has become too thin or see a J-hook pattern, rolled edges, dents, or uneven edges, you can fix them with a 600-grit polishing stone, also known as an Arkansas stone (photo). Stoning the land is a quick and simple way to restore land to its proper size with a sharp outside edge to minimize flashing.

Mike Beyl is Western tablet tooling specialist at Wilson Tool International, White Bear Lake, MN. Wilson Tool's tableting division provides compression tooling, including standard punches and dies, accessories, and custom-designed tool solutions, to the pharmaceutical, nutraceutical, industrial compression, confectionary, and other industries.
July 8, 2019
Facebook spacer Twitter spacer Twitter spacer Home
Supplier Resources
click below for more info
jrs pharma
Supplier Directory
Capsule Filling Equipment

(Equipment & Coatings)

JRS Pharma

Contract Formulation/
Manufacturing & Packaging

Recro Gainesville


Natoli Engineering

Dust Collectors/Filters
Camfil APC
Nilfisk Industrial Vacuums

Jost Chemical
JRS Pharma


Inspection Equipment
Natoli Engineering


Metal Detectors/X-Ray Detectors
Natoli Engineering

Mixers & Blenders

Pneumatic Conveying
Nilfisk Industrial Vacuums

Natoli Engineering
Wilson Tool

Storage/Bulk Handling

Tablet Presses
Kikusui USA Inc.
Natoli Engineering

Testing Equipment
Natoli Engineering

Natoli Engineering
Wilson Tool

Vacuum Cleaners
Nilfisk Industrial Vacuums

Weighing Equipment
T&C Solid Dosage Sourcebook
Peggy Wright
T&C Solid Dose Digest
Kyle Myers
T&C Solid Dose Digest
Kurt Beckman
T&C Solid Dose Digest
Nate Todd
Tablets & Capsules
Copyright 2019, CSC Publishing Inc. All rights reserved.
Tablets & Capsules Insight Newsletter