Eichenberger's core business is the rolling, hence cold forming, of threads and the manufacture of ball and slide screws (screw and nut). What is meant by "One Piece Flow" is production or assembly where manufacture is on the basis of individual work pieces which "flow" through the entire production system without intermediate storage or buffer. An appropriate assembly line can be quickly changed over; so that different products can be alternately assembled in small or even large unit numbers. Eichenberger has opted for the U-shaped assembly cell, where supply and extraction are located at the same end, the material flow takes place "outside" and the operators "inside" have sufficient room. Thanks to the One Piece Flow principle, work- and downtime are reduced, inventories decreased in production and tracking of the material flow ensured.
The self-regulating Kanban system supports the material supply of the assembly islands. It is a rolling container system which replaces the traditional delivery methods. Via the pull principle, also referred to as pull production, the employee removes the preassigned material required for assembly. The Kanban quantity is controlled by a simple visual inventory control.
Assembly of the ball screw in the flow
Added value via less waste is achieved by tightening up production processes via optimisation of procedures and losses in time and production eliminated. Potentials were able to be identified by creating an analysis of the current state. The project team established the optimisation focuses together with the employees concerned. After a very few weeks the assembly workstations in Cardboard Engineering were set up on flow principles and the logistics chain reimplemented according to the Kanban principle. Two One Piece Flow manufacturing islands were started up and the first ball screws were assembled in flow. It soon became evident that the targets set had been vastly exceeded.
The comprehensive multiplicity of variants and dimensions of the screw drives posed a particular challenge. The variations in batch sizes of 1 to about 100,000 pieces and increasing demands of customers in relation to cleanliness and precision were also points whose conversion to lean management made some demands.
Today the whole ball screw assembly is implemented according to lean criteria, including the logistics chain. In general a reduction in the error quota of 30 % has been achieved in assembly.