This glossary explains the terms used in tablet dies and punches, from punch and die anatomy and tooling standards to steel grades, coatings, tablet profiles and common tablet defects. It is maintained by EMMKAY INDUSTRIES, a tablet dies and punches manufacturer based in Delhi, India, supplying pharmaceutical, nutraceutical, ayurvedic, confectionery and veterinary manufacturers since 1983.
65 terms · Last updated:
Punch and Die Anatomy
Tablet tooling
The upper punch, lower punch and die used in a tablet compression machine to shape powder blends into tablets. The tooling guides the compressive force that forms a hard tablet of uniform size and shape.
Set (tooling set)
One set of tablet tooling contains 1 upper punch, 1 lower punch and 1 die. EMMKAY INDUSTRIES supplies tooling with a minimum order of 10 sets.
See: Product catalog
Upper punch
The punch that enters the die from above and compresses the powder to form the top face of the tablet.
Lower punch
The punch that sits in the die from below, forms the bottom face of the tablet and pushes the finished tablet out of the die during ejection.
Punch head
The part of the punch that contacts the compression rollers of the press. It receives compression pressure and maintains it. The head includes the head flat, dwell flat and head chamfer, and its geometry differs between TSM and EU tooling.
Head flat
The flat area on top of the punch head that receives compression force. TSM tooling uses a domed head profile, while EU tooling has a larger head flat.
Barrel and neck
The main body of the punch, which guides it smoothly through the turret. Barrel diameter identifies the tooling type: 25.4mm for D and DB tooling, and 19.0mm for B and BB tooling.
Punch tip
The end of the punch that directly forms the tablet. The tip diameter defines the tablet diameter, and the cup depth defines its surface curvature.
Cup depth
The depth of the curve on the punch tip. It determines the surface curvature of the tablet and sets the minimum possible tablet thickness, ranging from 0mm for flat-faced tooling to 3.0–5.0mm for deep concave.
See: Tablet sizing guide
Land
The narrow flat rim around the edge of a concave punch tip that strengthens the tip edge. Scoring on the land area accelerates further wear and can cause sticking.
Band thickness
The part of the tablet thickness added by the press settings (fill depth and compaction) on top of the minimum thickness set by the cup depth of the tooling.
Overall length
The total length of a punch, which must match the press specifications exactly. EU and TSM punches have different overall lengths. A punch shortened by more than 0.05mm through wear should be replaced.
Working length
The distance punches travel while inside the die. It directly influences tablet density and hardness.
Key (keyed punch)
A key on the punch barrel fits into a keyway in the turret and stops the punch rotating. Shaped, embossed and multi-tip tablets need keyed punches; round tablets do not. TSM tooling uses a Woodruff key and EU tooling uses a flat key.
Die
The part of the tooling that forms the cavity the tablet occupies. Its most critical dimension is the die bore.
Die bore
The opening in the die that shapes the outline of the tablet. It is ground to tight tolerances (±0.01mm) for a consistent tablet diameter and smooth punch movement. A worn, enlarged bore lets in more powder, making tablets heavier and less consistent.
Die taper
A slight widening at the entry of the die bore that helps air escape during compression and can reduce capping.
Die height
The height of the die, which determines tablet thickness and capacity.
Die OD (outside diameter)
The outside diameter of the die, which must fit the die pocket of the press. It identifies the tooling standard: 38.10mm for D, 30.16mm for B and DB, and 24mm for BB tooling.
Tooling Standards
D tooling
The largest standard tablet tooling: 38.10mm die OD and 25.4mm punch barrel, for tablets up to 25mm. D tooling is the most common tooling standard worldwide.
See: D tooling
B tooling
The medium tooling standard: 30.16mm die OD and 19.0mm punch barrel, for tablets up to 18.5mm.
See: B tooling
BB tooling (BBS)
The smallest tooling standard: 24mm die OD and 19.0mm punch barrel, for tablets up to 18.5mm. The smaller die allows more stations per turret. BBS is another name for BB tooling, where the S stands for small.
See: BB tooling
DB tooling
A hybrid standard that combines the B tooling die OD (30.16mm) with the D tooling punch barrel (25.4mm). It lets a B press make tablets up to 25mm, but only if the punch guides are bored to 25.4mm.
See: DB tooling
TSM (Tableting Specification Manual)
A tooling guideline from the American Pharmaceutical Association that uses US units. It is widely used in the USA and Japan and on Indian-made presses such as Cadmach, Rimek and ACG.
EU standard (Euro standard)
The tooling standard commonly used in Europe and adopted worldwide, found on presses such as Fette, Korsch, Manesty and IMA. EMMKAY INDUSTRIES manufactures to EU standard by default.
TSM vs EU tooling
Both standards use the same die outside diameters for D, B, BB and DB tooling. They differ in punch head geometry, key slot position and overall punch length.
Steel Grades and Hardness
EMMKAY Special Steel
A proprietary corrosion-resistant tool steel (55–60 HRC) developed for corrosive formulations. EMMKAY INDUSTRIES recommends it as the versatile, economical default for most formulations.
OHNS
Oil Hardening Non-Shrinking steel, 58–62 HRC. It is the default choice for about 70% of tablet manufacturing applications and typically lasts 3–5 million tablets.
HCHC (D3)
High Carbon High Chromium tool steel, 62–64 HRC. It is the standard recommendation for die bores because dies see more abrasion than punches. HCHC typically lasts 5–10 million tablets and costs about 20–30% more than OHNS.
S7
A shock-resistant tool steel, 56–58 HRC, with the highest impact resistance of any grade. It is recommended for deep concave designs and formulations that chip punch tips.
HRC (Rockwell C hardness)
The Rockwell C scale used to measure the hardness of tool steel. Higher hardness means better wear resistance but lower toughness. EMMKAY tooling ranges from 55–60 HRC for EMMKAY Special Steel to 62–64 HRC for HCHC.
Coatings and Finishes
Chrome plating
An electroplated coating (800–1000 HV, 5–15 μm) that reduces sticking and protects against corrosion. It is the standard coating at EMMKAY INDUSTRIES, included in base pricing, and extends tooling life by 15–25%.
DLC (Diamond-Like Carbon)
A very hard coating (2000–5000 HV, 1–3 μm) with the lowest friction of any common punch coating. It is used for sticky formulations and extends tooling life by 20–40%.
TiN (Titanium Nitride)
A gold-coloured coating (2000–2500 HV, 2–5 μm) that resists abrasion from calcium, iron and mineral ingredients. It extends tooling life by 30–50% or more.
CrN (Chromium Nitride)
A silver-grey coating (1800–2200 HV, 2–5 μm) with better corrosion resistance than chrome plating and good wear resistance, suited to formulations that are both corrosive and abrasive.
TiCN (Titanium Carbonitride)
A hard PVD coating and a harder variant of TiN, used where tooling wear from abrasive ingredients is severe. EMMKAY INDUSTRIES offers TiCN as an option on request.
PVD (Physical Vapor Deposition)
A vacuum process used to apply thin, hard coatings such as DLC, TiN and CrN to punch tips.
Mirror polishing
Polishing the punch tip to a mirror finish of Ra 0.05–0.2 μm, depending on the application. It reduces sticking and gives tablets a smooth, glossy surface.
Tablet Shapes, Profiles and Design
Flat-faced (FF)
A punch tip with no curve (0mm cup depth), used for scored, embossed and uncoated tablets.
Flat-faced beveled edge (FFBE)
A flat-faced punch tip with a beveled edge, which reduces chipping during coating.
Shallow concave (SC)
A punch tip with 0.5–1.5mm cup depth, the standard profile for coated pharmaceutical tablets.
Standard concave
A punch tip with 1.5–3.0mm cup depth, used for general-purpose tablets.
Deep concave (DC)
A punch tip with 3.0–5.0mm cup depth, used for thick film-coated tablets. S7 steel is recommended for deep concave designs.
Compound cup
A punch tip profile that combines flat and concave areas, used for branded tablets and special profiles.
Break line (score line)
A single or cross line on the punch tip that lets the tablet be split into doses.
Embossing and debossing
Text, logos or patterns engraved on the punch tip to mark the tablet. Most logos and text are debossed (pressed into the tablet), which is also easier to clean.
Caplet (capsule shape)
An elongated, oblong tablet shape and the second most popular tablet shape after round, made from 4mm to 22mm long. Capsule shapes need keyed punches to keep the shape aligned.
Multi-tip punch
A punch with 2 or more tips that produces several tablets per compression cycle, increasing output by up to 80% on the same press. On D tooling, 2 tips are common for 10–12mm tablets, 3 tips for 7–9mm and 4–7 tips for 4–6mm tablets.
CAD drawing
A technical drawing of the tablet and tooling design that the customer approves before custom tooling is made. EMMKAY INDUSTRIES provides CAD drawings within 24–48 hours at no extra cost.
See: Sample CAD drawings
Tablet Defects
Sticking
Tablet material sticks to the punch face, leaving a rough or incomplete tablet surface.
Picking
Small amounts of material are pulled from the tablet surface, leaving pits or marks, especially in embossed areas.
Capping
The top layer of the tablet separates during or after compression.
Lamination
Similar to capping, but the separation happens within the body of the tablet.
Weight variation
Inconsistent tablet weights, often caused by worn die bores that let more powder fill the cavity. If a defect appears only at certain stations, the tooling at those stations is almost certainly the cause.
Press and Process Terms
Rotary tablet press
A tablet press with a rotating turret of stations, each holding a die and a pair of punches, that compresses tablets continuously. EMMKAY INDUSTRIES supplies tooling for rotary presses with 16 to 65 stations.
See: Tablet press tooling
Turret
The rotating part of a rotary tablet press that holds the punches and dies. The punch guides in the turret must match the punch barrel diameter: 25.4mm for D tooling and 19.0mm for B and BB tooling.
Station
A position on a rotary tablet press that holds one die, one upper punch and one lower punch.
Pre-compression
A lighter first compression applied before main compression. Combined with the right punch tip geometry, it reduces air trapped in the tablet, which helps prevent capping.
Dwell time
The time during which the powder stays fully compressed. Short dwell times speed up production but can reduce tablet hardness; longer dwell times improve hardness but may lower output.
Compression force
The force the upper and lower punches apply together to form the tablet, typically 5 to 100 kN depending on tablet size and formulation.
Ejection force
The force needed to push the finished tablet out of the die, typically 50 to 500 N. Rising ejection force signals die bore wear, poor lubrication or formulation issues.
Tooling life
The number of tablets a tooling set produces before it needs replacing. Higher press speeds shorten it: a set rated for 6 million tablets at 60 RPM may last only 4.5 million at 80 RPM. Punch tips can be repolished 2–3 times.
Formulation Terms
Effervescent tablets
Fizzing tablets made with citric acid, tartaric acid and sodium bicarbonate. These ingredients are corrosive to standard tool steel and sensitive to moisture. Effervescent tablets are typically 18–25mm and flat or shallow concave.
Hygroscopic
Describes a material that absorbs moisture from the air, as many herbal extracts do.
Bolus
A large veterinary tablet for cattle, usually 18–25mm in diameter and made on D tooling.
Can't find a term, or need help choosing tooling for your press? Contact EMMKAY INDUSTRIES or read our tablet dies and punches FAQ.
Need Tablet Tooling?
Our engineers will help you choose the right dies and punches for your tablet and press.
Request a Quote WhatsApp →