In the manufacturing of the ceramic capacitors (a device capable of holding an electric charge), the first step in the process is the mixing of the raw materials to produce the ceramic powder to be utilized in the manufacturing process. This synthesized ceramic powder is then mixed with an organic binder prior to being cast into greenware tapes for the manufacture of the capacitors. Adding organic binder is similar to adding water to cement mix in order to be able to pour the cement. In this case, the binder is mixed with the powder and allows the powder to be cast into greenware tapes. The greenware tapes, after drying, have the consistency and thickness of a 5 � inch floppy disk. They are then made conductive by coating with a metallic ink, stacked, and cut into strips. The strips are then processed through a series of ovens that first slowly removes the organic binder and then sinters (bakes) the ceramic power into a hard, solid strip of ceramic material. These solid strips are later cut into the individual capacitors. The problem is to determine some of the parameters for the powder manufacturing process.
The process involved in the manufacture of the ceramic powder is made up of a series of steps and needs to be done in the most time effective manner.
The ceramic powder is produced by the following process:
- Three different raw materials, X, Y and Z , are first combined as powders in a large container in a ratio by weight of 10 : 3 : 1.
- The 20 kilogram batches of the raw materials are mixed for a period of 4 hours.
- This 20 kilogram mixture is then heated in an oven at a temperature of 600� C for a period of 8 hours to produce the ceramic powder, XYZ.
- The resulting material has consistency of chalk. Thirty (30) kilogram batches are ground up into powder to obtain particles with a specific maximum size during a 4 hour process.
- The particle size is determined by a screening process with about 85% of the ground material being acceptable. (The non-acceptable material can be used if it re-ground to the proper size.)
- Organic binder is then added to the acceptable ground powder in a ratio of 8 : 1 by weight (powder to binder) and mixed for 8 hours to produce the powder-binder mixture that is then cast into the greenware tapes for further processing.
The fabrication process for the greenware tapes requires 2.5 kilograms of ceramic powder per finished block. There are 1,000 blocks of greenware tapes produced every 24 hours. The process engineer also wants to produce enough extra powder so that if a problem occurs (oven or mixing unit breaks down, raw powder or organic binder shipment is one day late), the process can continue to run for 24 hours without a stoppage.
Problems dealing with the mixing, heating, and the manufacturing of greenware tape.