Quality Magazine

Case Studies: MNP Sorts Out Options

August 1, 2003
A sorting machine uses lasers and optical sensors to measure parts and sort them.

MNP Inc. (Utica, MI), one of the largest suppliers of automotive fasteners, recently made a strategic decision to implement 100% sorting to nearly all of its parts.

MNP already performed 100% sorting on some parts, but wanted to improve on this record. Possessing a wide variety of sorting equipment, MNP’s workers had enough experience to know what features were most important for its expanding needs. Considering the large investment required to meet its growing sorting requirements, MNP decided to scientifically determine which machines were most suitable by direct comparative testing.

The following features were selected for comparison:

  • Machine sorting capability (gage repeatability and reproducibility)
  • Ease of use. How much skill would be required of the operator?
  • Parameter set-up storage and recall
  • Data generation and networking
  • Maintenance required and how much downtime would occur during maintenance
  • Sorting rate in parts per minute
  • Cost



Laser sorting

After completing the testing, the final results pointed to the USS-1000 sorting machine from General Inspection Inc. (Davisburg, MI). MNP followed up the comparison by placing its largest single order for sorting machines.

The USS-1000 is an automated, 100% laser sorting system designed to eliminate foreign parts from reaching the end user. A combination of laser and optical sensors measure parts as they pass down a “V” track. As parts go through the laser beam, they are measured and compared to previously entered dimensions. Parts that meet the specified tolerances are accepted and those that fall outside the inspection tolerances are diverted into a reject bin.

In addition, the system has an eddy current option called Gi+. Typical eddy currents check for the defects by comparing the signature of the good part to the signature of a bad one. But, some defects may only have a slight difference in the signatures, causing a difficult sort and resulting in more false rejects. This option uses a zoom feature that allows it to focus on signatures, and distinguish between like signatures.

“Many of the features were not even available on other models,” according to MNP’s sorting supervisor, Michael Henry. “Some of the sorting equipment manufacturers still use DOS operating systems. The Windows capability lets us network data.”

General Inspection Inc.

(888) 817-6314

www.geninsp.com



Sidebar: Benefits

1. Allows for nearly 100% sorting of parts.

2. A combination of laser and optical sensors measure parts as they pass down a “V” track.

3. In addition, an eddy current test reduces the number of false rejects.