Tablet Pressing Tooling Terminology

There are common terms to use when discussing tablet pressing tooling and understanding this terminology can go a long way in using these presses. Here are some common terms listed in alphabetical order.

• Anneal: Heat treating process that is used on fragile punch tips in order to decrease the hardness of the punch cups and reducing punch tip fracturing.
• Bakelike Tip Relief: An undercut groove between the lower punch tip straight and the relief. It assures a sharp corner in assisting in scraping product adhering to the die wall.
• Barrel: This is the vertical bearing surface of a punch that makes contact with the punch guides in the machine turret for vertical guidance.
• Barrel Chamfer: Chamfers appear at the ends of the punch barrel and eliminate outside corners.
• Barrel Flutes: These are vertical slots that are machined into the punch barrel in order to reduce the bearing surface and assist in removing product int the punch guides.
• Barrel-to-stem Radius: The radius that blends the punch barrel to the stem.
• Cup Depth: The depth of the cup from the highest point of the tip edge to the lowest point of the cavity.
• Die: A component that is used in conjunction with the upper and lower punches. A die is responsible for the tablet's perimeter size and configuration.
• Die Bore: This is the cavity of the die that accepts the product for compaction and ultimately determines the sizes and shapes of the tablets.
• Die Chamfer: The die chamfer is the angled area that is between the top of the die and the die bore and assists in the guiding.
• Die Groove: The radical groove that is around the die that accepts the die lock in order to secure the die in position in the die table.
• Die Height: The die height is the entire height or overall length of a die.
• Die Lock: The lock of the die is the mechanism that is used in order to lock a die in the right position after it is installed in the die table.
• Die Outside Diameter: This is the largest diameter of a die.
• Die Taper: The die taper is the gradual increase in dimension. It starts from a given depth in the die bore and increases to the die chamfer. The die taper is normally used to release air from the die cavity during the compression cycle.
• Head: The head is the largest diameter of a common punch. The head contacts the machine cams and accepts the pressure from the pressure rollers.
• Head Back Angle: Sometimes this is referred to as the inside head angle. It is located underneath the top head angle or the top head radius, which contact the machine camming for vertical movement of the punch within the punch guides.
• Head Flat: This is the flat portion of the head, which makes contact with the pressure rollers and determines the maximum dwell time for compression.
• Key: The key is a projection of mild steel, which protrudes above the surface of the punch barrel. The key maintains alignment of the upper punch for reentry into the die. It is commonly used with embossed round tablet shapes when rotation of the punch causes a condition known as double impression.
• Key Position: The radial and height position of a key on the punch barrel. The key position is not something you will find on all tablet presses.
• Land: The land is the area that is between the edge of the punch cup and the outside diameter of the punch tip. The land adds strength to the tip and reduces punch tip fracturing.
• Neck: It is located below the head and it provides clearance as the punch cycles through the machine cams.
• Punch Length: This is the total length of a punch other than the flat face tablet configurations. 
• Stem: The stem is the area from the barrel to the edge of the punch tip.
• Tip Face or Cup: This is the portion of the punch tip that will determine the contour of the tablet face. The tip face or cup includes the tablet embossing.
• Tip Length: The straight portion of the punch stem.
• Tip Relief: The portion of the punch stem which is an undercut or made smaller than the punch tip straight. Can aid in reducing friction from the punch tip and die wall as the punch travels through the compression cycle.
• Tip Straight: This is the section of the tip that will extend from the tip relief to the end of the punch tip. The tip straight maintains the punch tip size tolerance.
• Tooling Set: The tooling set is a complete set of punches and dies to accommodate all stations in a tablet press.
• Tooling Station: This is where the upper punch, lower punch, and die converge at one station in a tablet press.
• Top Head Angle: This is the angle from the outside head diameter to the top head radius. The top head angle allows for sufficient head thickness and smoother camming.
• Top Head Radius: The radius on the top of the head, which blends the top head angle to the head flat. Some head configurations might consist of only the head radius without the head angle. The top head radius makes the initial contact with the pressure roll and allows a smoother transition into the compression cycle.
• Working Length: The working length is the dimension from the head flat to the lowest measurable point of the tip face and is responsible for the consistency of the overall thickness of the tablet.

What Are Tablet Presses?

Before we get into some common terminology, let's first understand what tablet presses are and their features. A tablet press goes by many names, such as tableting machine, tablet punching machine and pharmaceutical tablet presses. In general, a tablet press compresses powders into tablets of uniform size, weight, and shape while always containing the same exact quantity. Tablet presses are widely used within the pharmaceutical industry in order to manufacture uniform tablets.

Our Tablet Presses

Then we get into the tooling aspect. The basic unit of any tablet press is tooling that consists of two punches and a die called station. This works by the upper and lower punches coming together in the die that contains the tablet formulation. And they do so by creating a precise dosage of medicine, which is absolutely necessary because uneven doses of medicine is dangerous.