An Overview of Die Cutting Tolerances

In manufacturing, it is possible to come very close to desired dimensions, known as the nominal value of a dimension, but there will always be some variance. The allowed amount of variance is referred to as the manufacturing tolerance or part tolerance.  The tolerance allowed depends on factors such as materials used and type of project. Tolerance is expressed in terms of minimum and maximum limits, usually in units of measure, but possibly also as a percent of the nominal. 

For example, a 9-inch part made to a tolerance of ±0.005 inches would be acceptable to have dimensions between 9.005 and 8.995 inches.  If tolerance is ±5%, the acceptable length would be between 9.450 and 8.550 inches.  The smaller the tolerance, the closer the parts must be to nominal.  Parts made within a small error range are referred to as close tolerance.  

At Millennium Die Group, we provide steel rule dies for die cutting operations. Equipped with over 60 years of industry experience and a fully stocked die shop, we have the knowledge and tools to design and deliver dies that meet and achieve close tolerances at an effective cost.

 

Determining Die Cut Part Tolerances

Some of the factors that determine the tolerances that can be achieved by a die include:

  • Material being cut
  • Part design and size
  • Tool type, including rule height, type of dieboard, and type of steel rule needed
  • Production technique and skill of the die maker
  • Application environment

As a practical matter, tighter tolerances affect cost. Getting a very close tolerance can influence turnaround time, design complexity, and compromises in manufacturing processes. In some cases, we have found creative solutions to balance these factors. For example, in a die to produce membrane switches, the smaller internal features may require closer tolerances so that the components line up with circuitry.  After achieving a tolerance of ±0.003 inches, less tolerance is expected for the rest of the tool to meet cost targets.

Another example is a combination die. In this case, selected areas contain a machined part that can hold ±0.002, delivering what is needed where needed but providing cost advantages consistent with steel rule dies.

When creating a die for a customer, we work with them to achieve a tooling solution that is both effective and efficient.

 

Part Tolerances Achieved by Different Dies 

There are several types of die cutting tools available, which come with different benefits and disadvantages. At Millennium Die Group, we specialize in steel rule dies. These can typically achieve ±0.005 inches tolerance. As mentioned above, we have succeeded in delivering tools at ±0.003 in critical areas, given specific materials to be cut and particular die characteristics.

An alternate type of die that can achieve closer tolerance is solid mill dies—also known as custom milled component dies— in which the cutting edge is exposed when depressions are ground out of a solid block of steel to which the edge is still attached. Much higher tolerances (±0.001 inches) in manufactured parts can be achieved; however, this precision comes with greater costs and a longer production time for the die.

Steel rule dies are lower cost and more quickly produced than solid mill dies, but if you need a very close tolerance, a solid mill die would be a better option. Most importantly, steel rule dies can achieve a good compromise for precision, cost, and benefit.

 

Using Optical Comparators to Measure Tight Tolerances

Our team uses an Acu-Gage® optical comparator to ensure our finished dies fall within the specified tolerance. The machine allows us to measure and inspect the dimensions of each tool—and the die cut parts they are designed to produce—to verify they are within the acceptable range. As part of this inspection, we document the specifications in a First Article Inspection (FAI) report, which is shipped with the die.

 

Partner with Millennium Die Group for Your Steel Rule Die Needs

Millennium Die Group is an ISO 9001 compliant veteran-owned die shop that is fully committed to providing customers with high-quality steel rule dies that accommodate their part tolerance needs. By partnering with us, you benefit from our: 

  • Extensive die experience and engineering
  • Comprehensive inspection and quality control processes, including FAI reports
  • Responsive customer service team
  • Competitive prices
  • Quick turnaround

 

For more information about our die capabilities and learn how we can create a die to fit your specs and your budget, contact us today.