In a previous blog, I spend some time giving you a primer on laser-based length and speed measurement and the value it brings to industry. This versatile technology is so effective, that it is used across a wide scope of industries and applications. In this blog, I want to illustrate the power that this technology brings to the film and sheet production industry.
Let’s Stretch and Draw
Like most manufacturers, producers of film- and sheet-type products are under tremendous pressure to process and deliver products on time, on budget and to customer quality demands. And laser length and speed measurement plays an important role in accomplishing this. Manufacturers are using this gauging method to better control stretch and draw operations.
So, why is stretch and draw important? There are several reasons. Manufacturers need to:
- Draw down the product as thin as possible without breaking
- Make sure there is no draw and that all drive rollers are pulling the product down the line at the same speed
- Draw down the product to a very specific and accurate thickness
The Problem with Mechanical Measurement Systems
Most manufacturers currently measure stretch and draw by either trusting the speed that their production line drives are reporting or using a contact encoder in some way. Contact encoders are mechanical devices used to measure drive roller rotation and speed -- very much like the tachometers used on a bicycle wheel or shaft.
While drives are becoming more sophisticated and more accurate every year, the simulated encoder output from the drive cannot compensate for slippage. Every product has some amount of slippage on the drive roller. The amount that the product slips can change based on texture, product composition or even tension at other points on the line. A contact encoder attached to the drive roller has the same problem.
A contact encoder riding on top of a film or sheet product has even more problems. The wheel can either wear down or have dirt build up, both of which change the calibration. This, along with the same types of slippage problems, makes any sort of contact measurement a poor choice when high accuracy is desired. Contact encoders can also affect material quality and create waste because of damage to the product’s surface and speed control issues to maintain product thickness.
Laser Measurement is King for Accuracy and Controlling Quality
The best solution for accurate measurement of stretch or drawdown is a non-contact length and speed measurement device, like NDC’s LaserSpeed Pro gauge. This technology uses a unique, laser-based measurement technique unlike anything else on the market. Since it measures the product itself and not the roller, slippage is not a problem. Also, with its ultra-high gauging accuracy, manufacturers can be confident that the stretch or draw measurement will be reliable and correct.
By placing a non-contact, laser gauge at each critical measurement point along the production line, manufacturers can accurately determine the amount of stretch or drawdown of their product, eliminating any guessing or uncertainty. Manufacturers also realize significant savings by reducing scrap, eliminating maintenance on mechanical measurement devices and increasing production line uptime.
If you're wanting to learn more about how you can better control stretch and draw applications, check out our LaserSpeed Pro gauge. We’re ready to help solve your toughest challenge.