Material handling pallet

In 1999 when Kodak was still a photographic film based company, they were in the middle of opening a major film production facility in China. A critical part of their operation was the handling of very expensive light sensitive silver emulsions. The key to this entire process was the design of a rotationally molded container, referred to as a tote bin.

Unfortunately the design developed by one of their vendors catastrophically failed to pass their extremely stringent specifications. This major setback placed the entire production startup operation in jeopardy, potentially costing the company millions of dollars in lost revenues.

It was at this point we were called in to solve their problem. Our mission was to provide Kodak with a design that satisfied all their specifications within 2 months. The following case study will provide you with a summary of what took place.

Since the specifications were much too lengthy to provide here, a summarized list of the most challenging requirements have been listed below:

Tote Shape is square with radii all corners, single wall for thermal conductivity. Container size must comply with industrial washer specifications  

Base pallet must comply with handling by AGV fork trucks.

Tote upended & washed with detergent through industrial washer

Tote/pallet assembly must support 800 kg in all orientations. No leaks permitted into any enclosed walls are permitted.

All surfaces to be smooth for thorough cleaning and drying to prevent bacteria formation. All surfaces must be smooth and devoid of features which could trap water or propagate water droplets. 12 bolts between tote and base must be 314 SS  

Shortly after meeting with Kodak’s development team and reviewing the product specifications, we examined the previous designs proposed for the material handling module. Many of the concepts were extremely complicated, structurally inadequate or totally impractical for rotational molding. 

Our objective was to propose a rugged simple design that could easily be rotationally molded. The following concept sketches illustrate the basic thought processes which lead to the final design.

The floor of the main tote was designed with a spherical surface for improved dimensional control. The pallet was totally redesigned with openings for reinforcement and matching curved support ribs. Care was taken to assure that forklift openings were properly located.

Concepts derived from the sketches were further developed in CAD. The following images illustrate design refinement and details.

Adequate clearance was provided around the perimeter between the lid and tote bin

The top surface of the lid was domed to eliminate any potential warping, inherent in the rotational molding process.

The pallet design was optimized for maximum strength and ease of molding. Structural rigidity was maximized with molded though holes which created boxes and columns. 

On the underside of the pallet web-like ribs further reinforced the overall structure by tying all walls together.

Shut-offs between both mold halves created the opening for forks without adding to tooling complexity.

The top surface of the pallet was domed to match the curved surface of the tote bin.

As the overall design developed we began to focus our attention on the attachment of the tote bin to the pallet. This was a major challenge based on the fact that the inside wall of the tote had to remain smooth with a molded in insert.

Many concepts for inserts were sketched and discussed as shown in the following pictures.

Since the design of this specific feature was so critical we designed a small 15” cubic tote with many different insert designs. A prototype rotational mold was then quickly constructed to mold parts for testing.

Parts were molded and tested for pullout strength as shown in the following photographs.

After an insert design was accepted based on ease of molding and strength, the production design was finalized and patterns were machined directly from the CAD files by Wheeler Boyce (a division of Lakeland Mold).

A dimensional inspection report for all the patterns revealed a few dimensional discrepancies which had to be corrected.

First production samples were molded within a month after the patterns were approved, well before the critical target date. The project was a resounding success, enabling Kodak to meet their production startup in China. The following pictures show the pallet with a smaller tote which was also designed as part of this sophisticated material handling system.