Parts Handling Optimization

Q. We currently clean, phosphate and adhesive-coat metal parts used in the automotive industry, producing in excess of three million parts per day. We process under lean principles, but due to the volume, we process in controlled batch sizes. We are continuously improving our processes and are researching new equipment technology. We are interested in cleaning and coating equipment that will eliminate part-to-part contact. I am not sure if this means racking systems or one-piece flow. The define stage of our project begins soon. Do you have any suggestion for where we might look for equipment to meet our needs? —W.B.

A. One-piece flow is sometimes proposed as an ideal state for almost all materials-handling issues in manufacturing as a whole, not just cleaning. One-piece flow is a simple concept in principle since it targets handling and delivering one part at a time, in the right condition, to the right place at exactly the time it is needed. While this should be a goal to consider with any cleaning and materials-handling system, practical constraints and cost often will require deviation from this ideal state.

Two of the most significant factors related to materials handling will be part size and geometry. Obviously, handling three million tiny parts is generally less expensive from an investment and footprint standpoint. Geometries with large surface areas that contact and nest or may have blind holes will be more difficult to handle and, specifically, to clean and circulate cleaning fluid and rinse through.  

Practical considerations for today’s parts handling will often involve the use of a rotating barrel for cleaning and handling of smaller, more intricate parts. While this will not keep parts from touching, it will minimize the contact time in any specific area, enabling the cleaning and coating to take place more uniformly.

True one-piece flow would be more likely and necessary the larger the parts you are dealing with. Washers utilizing hanging or flat conveyorized movement are well-equipped to handle most medium to large parts. I would recommend you gather part sizing and geometry information to discuss with suppliers along with details regarding your current process (stages, chemicals, effectiveness and desired changes). Then check the information on the Products Finishing site, PFonline.com, under the Suppliers tab to find some businesses that can assist you.