How to Keep Cut-to-Length Lines Within Tolerances

(Cut-to-Length (CTL) lines - Source: Herr-Voss)

Cut-to-Length (CTL) metal cutting operations have customers placing increasingly tight tolerance requirements upon them. Formerly the cut-to-length lines only need the resulting metal blanks to conform to the final product dimensional needs. Now there are other machines and operations that expect metal blanks to arrive within +/- .015 inch (0.380 mm) or even as tight as +/- .005 inch (0.130 mm). This new demand for precision means that cut-to-length metal slitting lines have to apply tighter tolerances throughout along with specific technology for keeping the blank shapes consistent throughout.

Gripper feeds are one of the main tools for achieving higher tolerances. We will cover how gripper feeds assist with consistent production accuracy after we delve into what we mean by tolerances on cut-to-length production lines.

Cut-to-Length Metal Slitting Line Tolerance Parameters

There are no perfect parts from metal slitting lines, whether they are cut-to-length operations, or full coil operations. All the products have some degree of camber deformation.

Camber for coil operations shows the devil is in the details. Camber is how far off the side edge of a strip from a straight edge. There are different types of camber that affect semi-continuous metal slitting operations.

Minimizing Camber for Sweep and Snake for CTL operations

Sweep is a more or less uniform curvature along the edge of a metal strip. Snake, as you might imagine, snakes back and forth along the strip edge. Wider metal slitting lines usually experience the sweep form of deformation.

Snaking is a problem that tends towards narrow slitting operations, and is generally less common. Both of these imperfections come from strips with uneven edge lengths.

Cut-to-Length Problem Blanks

There are no exact squares coming off metal coil slitting cut-to-length lines. Every blank either has some property of a  parallelogram or is cambered with a definite curvature.

A parallelogram metal blank has width and lengths even, but the diagonal measurements are different. Cambered parts have a constant width but the edge lengths are different.

Both of theses forms of deformed parts will be present depending on the errors within the coil or the line. Camber is always present making a straight parallelogram impossible.

Achieving Close Cut-to-Length Tolerances

The American Society for Testing and Materials (ASTM) defines out of square tolerances based on half the difference of one side's deviations from a 90 degree line at each corner.

The more usual way of achieving this square tolerance level is to simply measure the diagonals and make sure they are equal within tolerances. ASTM's standard for camber from a coil larger than 12 inches is 1 inch in any given 20 feet (25 mm in 6.1 m).

Grip Feed Measuring for CTL Lines

Sometimes referred to as hitch or side feed systems, these grip feed measuring systems have been around for years. Aside from assuring accurately produced cut-to-length metal blanks, they also prevent damage to the presses or shear.

These systems can provide similar tolerances as automatic press feed devices. Theses work by hydraulic actuated and mechanical linked grippers delivering a precise sheet geometry to the high-speed CTL/blanking lines.

Grip feed systems are able to achieve 250 fpm +  feed speeds at the accuracy level required.

Understanding how to keep CTL within tolerances, as well as what the common errors are, can keep precise blank production flowing as the metal slitting line was designed to do.

To return from this Cut-To-Length page to the Strip Metal Coil Processing Home page, click here.

Some Cool FREE Stuff....


Would you like a Free Report that shows
you exactly what to look for when buying
used machinery? 

My Free Report is 34 pages packed with

strategies that will help you avoid getting
a “lemon” and methods for saving thousands
of dollars. 

  • Cost-Benefit of Used vs. New
  • 18 Key Points to consider when comparing used versus new equipment.
  • 11 Inspections You MUST Do
  • A Checklist for 11 Inspection Types that you HAVE to do or risk getting burned.
  • Comparing Domestic vs. Foreign

Get Your Free Report Here



Are you looking to buy or sell a piece of used equipment but are hesitant to take the next step? 

I have two decades of experience that I can share with you.  To schedule a consultation with me, simply email or call me and I will set a time with you to discuss the details 


or call direct:

Office: 1-888-394-0181

Mobile: +1-905-334-9282

You can also contact me by filling out he contact us form below

Contact Us

Please note that all fields followed by an asterisk must be filled in.

Please enter the word that you see below.



Free Machinery Listing

Do you have a piece of used machinery you would like to sell? can
help find you a buyer. 

Clear floor space and put some cash into your bank account.  Posting your equipment is quick
and easy.  Click here to advertise your, company, service or equipment.

SIGN UP below to be the FIRST to know

FREE Website Updates

This website is constantly expanding, adding new and relevant information. Always making sure coil processing makes sense to you. To stay within the loop for all the NEW and EXCITING information on coil processing, just put your name and email below and I will keep you up to date...


Please note that all fields followed by an asterisk must be filled in.

We Respect Your Privacy and We Will Never Share Your Information

Change Language Here:

Protection Face Mask Balaclava + 2 FREE Gifts!

[?]Subscribe To This Site
  • follow us in feedly
  • Add to My Yahoo!
  • Add to My MSN
  • Subscribe with Bloglines

Top 3 FREE Tips

to increase efficiency

  1. Use appropriate technology and by-pass manual labor where possible for the roll and coil changeovers.
  2. Coil cars can also cut transition and changeovers.
  3. Consider material handling elements such as coil storage racks if there is not a crane installed for keeping a coil car active.
Read More

This form  is an offer to join the Strip Metal Coil Processing Group!!!

Just provide your information below and BAM your in!!!!

Enter Your E-mail Address
Enter Your First Name (optional)

Don't worry — your e-mail address is totally secure.
I promise to use it only to send you Strip Metal Coil Processing Newsletter.