The problem
The client company is a supplier of knives used in the food service industry. The units use a replaceable knife, made by forging an iron base alloy, heat treating, and then machining it. They wanted to redesign their product to address several problems:
- The present design had been in production for many years and had been copied by third party suppliers who were taking an increasing share of the spare parts market.
- The forging process was unique to this product in their company and was costly to operate.
- The material used for knives was subject to corrosion by the cleaning solutions required to maintain food grade cleanliness.
Why it was difficult
The criteria required a total rethink of the design and manufacturing process. The aim was to develop a unique and cost-effective product which would improve corrosion performance and reduce manufacturing costs.
The Stellite solution
We reviewed the objectives against the full range of Stellite technologies - casting, wrought products, overlays, coatings, and finishings. The final design incorporated a total product approach that achieved all the required objectives. The basis of the solution was the Stellite experience in providing cutting knives in other industries that incorporate PTA (plasma transferred arc) welded edges of Stellite material on less expensive stainless steel blanks. The keys to the solution were our understanding of both the welding process required for the overlay and the subsequent machining techniques needed to produce a finished part economically.
The final product uses a stamped stainless steel blank which has a precision edge overlay of Stellite on the cutting edge. The stamping and welding processes were developed simultaneously to cut down on distortion and the machining required.
The result
In order to minimise the capital investment and ramp-up time, the customer contracted Stellite Coatings to provide welded blanks rather than bringing the process in house. The customer elected to do only the final machining and sharpening. Stellite was able to put in place a dedicated manufacturing cell and ramp up from the development phase to full production in 90 days.
The customer has been able to recapture substantial market share in replacement parts with this unique product. In addition to the improved corrosion performance, the Stellite-edged knives provide superior cutting and longer life.