EMMKAY INDUSTRIES has manufactured tablet dies and punches in Delhi, India since 1983. This guide covers how to evaluate tooling quality before it reaches your press — the inspections, documentation, and measurements that separate precision tooling from substandard alternatives. It complements our maintenance guide (care after purchase) and our tooling lifespan guide (how long tooling lasts).
Why Quality Varies So Much Between Manufacturers
Two tooling sets can look identical and cost very differently — because quality lives in details you cannot see at a glance:
- Steel certification: Certified steel comes with a mill test certificate stating grade and composition. Uncertified steel is an unknown — it may not hold the wear resistance you are paying for.
- Machining method: CNC-ground tooling holds tighter, more repeatable tolerances than manually ground tooling. Surface finish directly affects sticking and ejection.
- Heat treatment verification: Proper tooling is hardness-tested per batch. Heat treatment without verification leads to premature wear or brittle, chipping tips.
- Dimensional inspection: Measured inspection catches an oversized die bore before it ships. Visual-only inspection does not. A die bore just 0.05mm oversized causes tablet weight variation from the first batch.
What to Check on Delivery — Dimensional Inspection
Inspect incoming tooling against the agreed drawing. The key dimensions and typical tolerances are:
| Dimension | Typical Tolerance | Why It Matters |
|---|---|---|
| Overall punch length | ±0.05mm | Controls tablet weight consistency across the turret |
| Tip diameter (round) | ±0.01mm | Determines tablet diameter and fit in the die bore |
| Tip diameter (shaped) | ±0.02mm | Maintains shape fidelity and embossing |
| Die bore diameter | ±0.01mm | An oversized bore causes weight variation and capping |
| Die bore surface finish | Ra ≤ 0.2µm | A rough bore increases ejection force and sticking |
| Working length | ±0.05mm | Affects compression force uniformity |
Keep a record of these measurements for each tooling set. A simple log of die bore diameters and punch lengths lets you track wear over the tooling's life and plan replacements before quality drops.
Documentation You Should Request
EMMKAY INDUSTRIES provides the following documentation on request — ask for it when you place an order:
- Material Test Certificate (MTC) — confirms steel grade (OHNS, HCHC/D3, S7, or EMMKAY Special Steel) and heat number for traceability.
- Hardness Test Report — confirms the tooling was correctly heat-treated and verified per batch.
- Dimensional Inspection Report — actual measured values against drawing tolerances.
For help matching steel grade to your formulation, see our tablet die steel grades comparison and our OHNS vs HCHC vs S7 guide.
Red Flags — Signs of Substandard Tooling
- Visible pitting, scratches, or dull spots on punch tip faces
- Visible grind marks or scoring inside the die bore
- Inconsistent surface finish between punches in the same set
- No material, hardness, or dimensional documentation available on request
- Pricing well below market (under ₹800 per set for standard round tooling) — usually a sign of uncertified steel or skipped inspection
Heat Treatment — Why Verification Matters
Heat treatment determines how well tooling resists wear without becoming brittle. The goal is a balance: hard enough to resist abrasion, tough enough to survive compression without chipping. This balance matters most for punch tips, the most fragile part of the tooling.
Properly heat-treated tooling has its internal stresses relieved through controlled processing, which reduces chipping and cracking during compression. The critical point for buyers is verification — quality manufacturers test and document hardness per batch rather than assuming it. When hardness is verified and recorded, you can trust the tooling will perform consistently. Read more on extending tooling life in our lifespan guide and maintenance guide.
Frequently Asked Questions
What should I check when receiving new tablet tooling?
Inspect incoming tooling against the agreed drawing: overall punch length, tip diameter, die bore diameter, die bore surface finish, and working length. Compare each against the drawing tolerances and log the measurements so you can track wear over the tooling's life.
Why does die bore surface finish matter?
Ra is the average surface roughness, measured in micrometres. A die bore at Ra 0.2µm or smoother minimises ejection force and tablet sticking. A rough bore grips the tablet during ejection, raising friction and accelerating wear on both the die and the lower punch.
What documentation should I request from a tooling manufacturer?
Request a material test certificate confirming steel grade and heat number, a hardness test report confirming heat treatment, and a dimensional inspection report against drawing tolerances. EMMKAY INDUSTRIES provides this documentation on request.