Precision Metal Stamping Services & Die Specification Guide

This page is a specification guide for buyers of stamped metal parts. It draws on preserved plant records from Clifton Precision Tools Limited to explain how stamped parts are specified, how progressive and compound dies differ, what drives tooling cost and lead time, and what to confirm before releasing a print. It is presented as archival reference, not as a current vendor profile or an offer to quote.

How a Stamped Part Is Specified

A stamped part specification begins with the material and temper. The alloy, thickness, and temper determine formability, springback, and the force the die must apply. Buyers should state the material standard, the nominal thickness with tolerance, and the temper or condition. When the temper is left open, the die may be built for one condition and then produce inconsistent parts when the mill ships another. The preserved plant record shows that tool design and machining were supported by software such as NC Graphics toolmaker for 2D and 3D tool design and 3D surface manipulation, which allowed the toolmaker to model the strip and the die before cutting steel.

The strip layout is the next element. A strip layout shows the sequence of operations, the carrier web, the pitch, the bridge width, and the material utilization. It also shows where pilots, gauges, and idle stations sit. A clear strip layout lets the buyer see how the part is carried through the die and where the scrap is removed. The plant record lists Optris virtual press simulation solver software for die development and stress analysis, and PAM DieMaker for interactive die addendum creation and quick modification within the stress analysis software. These tools supported the practice of testing a strip layout digitally before committing to a die build.

Tolerance stack is the third element. A stamped part accumulates variation from material thickness, die clearance, press deflection, and the number of operations. The buyer should identify which dimensions are functional and which are reference, and should avoid tightening tolerances that do not affect fit or performance. The plant record notes that a Laser Arm Scanner was used for quality inspection by comparing digital models with CAD to ensure products met intended design and performance characteristics within specified tolerances. That inspection method depends on a print that states tolerances clearly and consistently.

Burr allowance is the fourth element. Every sheared edge carries a burr, and the specification should state the acceptable burr height and the side of the part on which the burr is permitted. If the burr is not specified, the die may be built to a default that does not match the assembly. The buyer should also state whether edges will be deburred, tumbled, or left as-sheared, because that choice affects handling and cost.

Progressive Dies and Compound Dies

A progressive die performs a sequence of operations at separate stations as the strip advances. Each stroke completes one station, and the part is carried forward by the strip until it is cut free at the final station. Progressive dies suit higher volumes because they combine piercing, forming, and blanking in one tool, and they can include idle stations for adjustment. The trade-off is a longer strip, a larger die, and a greater tooling investment. The preserved plant record documents six CNC Hurco machining centres with Ultimax software and a travel range of 1700 x 600 x 500, one Zayer CNC machining centre with Heidenhain 426 control and a travel range of 4000 x 2500 x 1500, and one Fil CNC machining centre with Heidenhain 426 control and a travel range of 2000 x 1000 x 1000. Those ranges indicate the size of die components the plant could machine, which is relevant when a progressive die grows beyond the capacity of a smaller shop.

A compound die performs blanking and piercing in a single stroke at one station. The part is cut free on the same stroke that pierces it, which reduces the number of strokes and can improve dimensional consistency between the hole and the outside edge. Compound dies are often chosen for flatter parts, for lower volumes, or when the tolerance between the hole and the edge is tight. They generally require less strip length than a progressive die but can be more demanding to build because all operations must align in one closing.

The choice between progressive and compound is a specification decision, not a preference. It depends on volume, part geometry, tolerance stack, material thickness, and the acceptable burr. A buyer who states the annual volume and the functional dimensions gives the toolmaker the information needed to recommend one type over the other. The plant record also lists Autocad 2000 as industry standard software and Rhino 3D for solid modelling and 3D surface manipulation, which supported the design office in comparing die concepts before a build.

What Drives Tooling Cost and Lead Time

Tooling cost is driven by die type, number of stations, die size, material thickness, and the precision of the tolerance stack. A progressive die with many stations and tight tolerances costs more than a compound die with a simple blank. Hardened tool steel, coatings, and replaceable inserts add cost but can extend die life. The buyer should expect the toolmaker to explain which features drive the price and which tolerances could be relaxed without affecting function.

Lead time is driven by design review, die design, machining, tryout, and sample approval. The preserved plant record shows that the design office used NC Graphics toolmaker, Machining Strategist as a 3D machining package, Optris virtual press simulation solver software, and PAM DieMaker. Simulation and addendum software can shorten tryout by identifying stress and material flow issues before the first cut. The record also notes Renishaw 3D scan software for full reverse engineering capabilities and a Laser Arm Scanner for reverse engineering, re-design and re-engineering of parts, and capture of hand-worked changes for CAD. When a buyer supplies an existing part rather than a print, scanning and reverse engineering add a step that must be scheduled.

The buyer can reduce lead time by supplying a complete print, a clear strip layout expectation, a material and temper callout, and a sample or CAD model where one exists. Incomplete information forces the toolmaker to make assumptions, and assumptions are resolved late, during tryout, when changes are most expensive.

What to Confirm Before Releasing a Print

Before releasing a print, confirm the material standard, thickness and tolerance, and temper. Confirm the strip layout or ask the toolmaker to provide one for review. Confirm the die type and the number of stations. Confirm the tolerance stack and identify which dimensions are functional. Confirm the burr allowance and the permitted burr side. Confirm whether edges will be deburred. Confirm the surface finish and any coating or plating. Confirm the inspection method and the sampling plan.

The preserved plant record shows that inspection could compare digital models with CAD using a Laser Arm Scanner, and that analysis could be performed on actual parts digitally for FEA or CFD. Those methods depend on a print that states the nominal geometry and the tolerance zone. A print that leaves the datum scheme unclear or mixes reference and functional dimensions will produce inspection disputes even when the parts are within the intended design.

Finally, confirm that the print states the revision, the units, and the projection. A print without a revision level cannot be controlled, and a print without units invites a costly mistake. The buyer should keep a record of the approved strip layout and the approved sample, because those become the reference for production.

Archival Context and Scope

The capabilities described on this page are drawn from preserved plant excerpts of Clifton Precision Tools Limited and are presented for archival reference. They describe equipment and software that the plant record documents, including CNC machining centres, die development and stress analysis software, and 3D scanning for reverse engineering and inspection. They are not a statement of current capability, current capacity, or current order intake.

This guide does not offer live quoting, does not accept orders, and does not claim successor status to any entity. It is a specification reference for buyers who need to understand how a stamped part is specified and what to confirm before releasing a print. Buyers should verify any supplier's current capabilities directly with that supplier.