Learn about tolerance capability for every design requirement

Everything you need to know before you sign up to Tolcap.

What is Tolcap?

Tolcap is a method for predicting process capability during the earliest stages of design and BEFORE production starts. It produces reliable tolerance capability data for every product design need.

What does Tolcap predict?

Given a manufacturing process, component material, a dimension and its suggested tolerance, Tolcap predicts an achievable process capability and ppm (rejected parts per million) of the manufacturing process. Allowing product designers to assess the viability of their suggested process, material, dimension, tolerance combination.

Alternatively given a manufacturing process, component material, dimension, and a suggestion of how many rejected manufactured parts the designer would consider acceptable (either the required Cpk or ppm) Tolcap will suggest a suitable tolerance for the dimension.

Why does Tolcap predict Cpk rather than Ppk?

Richard Batchelor addresses this frequently asked question in his blog Cpk, Ppk, PPM and Tolcap: Why Tolcap predicts Cpk. Tolcap's Cpk / PPM relationship.

Who can use Tolcap?

Product designers, manufacturers, engineers, design consultants. Anybody involved in the product design, specification or manufacturing process seeking to improve product quality, reduce cost, avoid loss, manufacture right first time, solve production headaches and accelerate product introductions.

Why is Tolcap useful?

Designers want to demand tight dimensional tolerances to achieve fit and function design goals. But specifying too tight a tolerance may result in a need to impose special controls on the manufacturing process with consequent higher manufacturing costs, or may even require a move to a more expensive manufacturing process. A wide tolerance may be cheaper to manufacture, but the larger dimensional variation may result in poorly fitting parts, costly rejects and product failures. Given your proposed process, material and your specified tolerance Tolcap predicts the manufacturing process capability you can expect (or the tolerance you can achieve for a target process capability). This enables you to work out the costs of ensuring adequate quality of your components - maybe even to improve your designs by re-distributing tolerances between component dimensions in a stack-up for example.

Tolcap also enables you to estimate quickly the part rejection rates achievable using alternative manufacturing processes and materials, enabling manufacture by the most cost-effective process and material.

The Tolcap wizards prompt the designer to think about important factors which affect process capability.

When is Tolcap useful?

Design engineers commonly employ Tolcap during initial component design to help them establish

  • workable dimensional tolerances
  • suitable manufacturing processes
  • suitable manufacturing materials
  • and
  • estimates of potential part rejection rates.

However, Tolcap has uses throughout the production process: from establishing whether your final production material component requires different tolerances to your prototype material component, to educating data driven manufacturability conversations with your supplier.

For which manufacturing processes and materials can Tolcap be used?

Tolcap provides tolerance capability data for over 80 different manufacturing processes within the following categories:

  • Cold drawing and rolling
  • Cold forming
  • Elastomeric and composite moulding
  • Extrusion
  • Hot forging
  • Machining
  • Non-traditional machining
  • Plastic moulding
  • Powder metallurgy
  • Sheet metalworking

Can I rely on Tolcap's data?

The chances are you already do!

In the last 24 hours you’ve probably used a household appliance, personal grooming or health care product which Tolcap helped bring to market. Over the last 15 years many of the planes and other vehicles you have travelled in will have depended on quality engineered components designed with the aid of Tolcap data.  

Tolcap’s data is the result of 20 years work with some of the world's largest, most respected and most innovative brands.
Learn more: Who uses Tolcap?  

What manufacturing factors influence Tolcap predictions?

The base tolerances, process capabilities and reject rates suggested by Tolcap are determined by the manufacturing process and component dimension input. Tolcap’s base predictions take into account real world issues such as tool wear and long term process shift; they assume good toolmaking practice and due attention to part monitoring are employed throughout the life of the manufacturing tool.

Tolcap has three wizards which allow additional factors to be taken into consideration:

Material Effect Wizard - For many manufacturing processes the ideal dimensional tolerance depend on the component material. For these processes Tolcap offers a list of typical materials and provides you with material specific results.

Geometry Effect Wizard - Tolcap does not address geometric tolerancing issues but does make allowances for influencing geometric factors e.g. manufacturing processes that simultaneously produce dimensions in multiple planes, components with unsupported slender regions, complex set ups required by parts with repetitive features, or characteristics of interest that cross mould or die split lines.

Additional Variation Wizard – This wizard allows real world limitations to be taken into account: older machinery; or component size, geometry, weight or material that challenge the manufacturing machines capabilities.

Why should I trust Tolcap’s predictions?

The data in Tolcap maps represents good practice for the manufacturing process concerned. The maps are empirically based on real, in process data, enhanced with information from a wider range of sources including international standards, specialist organisations, engineering texts and experimental studies. Particular maps may well include as many as twenty different data sources.
Tolcap data is known to be consistent with processes that are well established and fully developed. The predicted values of Cpk have proved to have very close correlation (98%) with SPC results.
Read more in our Blog: The Provenance of Tolcap: its Origins and Validation.

What is web-based software?

Web-based software is software you use over the Internet with a web browser. You don't have to install any CDs, download any software or worry about upgrades. In fact you don't have to worry about anything technical. You can just focus on your job while we handle all the security, uptime, backups and upgrades.

Is the Tolcap platform reliable?

We take reliability and security very seriously. Our solution is 100% cloud based with no single point of failure. It is managed by our own in house technology team and monitored 24/7 to ensure 99.99% uptime.

How much does it cost to use Tolcap?

Up to 5 users£2,495 per year + VAT
Up to 10 users£3,995 per year + VAT
More than 10 usersPlease contact us

Learn more on our Pricing page.

Is there a trial period?

Yes, we provide a 1-month free trial for you to experience just how much value Tolcap can contribute to your business. We'll be in touch with you during the trial to make sure you're happy with everything and are making the most of Tolcap's features and benefits. We'll also discuss your ongoing requirements so your access to Tolcap can continue uninterrupted at the end of the trial. You won't be charged anything if you decide to discontinue using Tolcap at the end of the trial period.

Are there signup fees, termination fees or other hidden fees we should know about?

Definitely not. You just pay as you go at the start of each year (or month) and can cancel your account at any time.

How can I get help if there is a problem?

Tolcap has a clear and simple system for giving feedback, either for reporting problems or giving ideas for future developments. Just click the "Feedback" link in the heading when you are logged in. We also provide a dedicated support email address.

Is this a long-term commitment?

We never lock anyone into a contract. We just don't believe in that approach and want you to use Tolcap for as long as you need it. Our customers can cancel at any time, no questions asked.

What browsers are supported?

Tolcap runs on all major browsers: Chrome, Firefox, Safari, Edge, Internet Explorer, Opera.

Our corporate Internet access is restricted, how can we get access to this software?

Many of our existing customers have Internet access restrictions. However, IT departments can in many cases apply rules to allow specific access to the Tolcap website. Talk to your IT department about removing restrictions to *.tolcap.com.

Tolcap includes:

  • Calculations for over 80 manufacturing processes
  • FREE trials for business users
  • Low cost business licences
  • No long term contract
  • No set up charges

Our video guides are designed to demonstrate the power of Tolcap.