Question

2. A major home appliances company produces compressors for their refrigerators in one of their plants. The most critical part of a compressor is called crank which is made from cast iron. The surface quality of the crank directly affects the energy consumption and the noise level of the refrigerator Therefore, it has utmost importance in the compressor production. The process of crank manufacturing starts with sand casting process. Casting department is a separate building only dedicated to casting and cleaning of the cranks. Cast and cleaned parts are then transferred to machining building which is located nearby. In the machining building, parts are first placed on the racks based on the batch size and wait for their turn to be processed. Parts are machined first in a CNC milling machine where the necessary surfaces are rough machined. Then, parts are cleaned using sand blasting technique to remove the burrs occurred as a result of milling. Sand blasting station is located near the milling machines. The parts are then taken into grinding process where three different locations on the crank which interact with the compressor's body are ground to have very fine surface roughness. The parts are taken into coating area where the surfaces are coated with a protective a thin layer for better lubrication and hence wear resistance during working conditions. During coating parts are placed into metal baskets and they are dipped into a tank filled with chemicals. After coating parts need to dry up, therefore they are placed in a room with controlled temperature/humidity and kept there for a while. Parts are then put back into the racks by the workers once they are dry. Workers are observed to rush this process due to large number of accumulated parts in this area, Parts are transferred to an assembly station which is a separate closed area within the same building. Some parts are randomly chosen and taken into quality control department where the dimensions, tolerances, and surface roughness are controlled before assembly starts. If some parts are observed to have surface defects on them, then the whole batch is inspected and the defective ones are sent back for re-coating. At the end of assembly process, some compressors are selected and they are tested for long hours under harsh working conditions. If the performance of the tested compressor is found not adequate, then production is stopped and the quality control team investigates the whole process starting from the beginning. a) (10 pts) Develop the process flow chart for the present system on the next page --> b) (20 pts) Propose only two improvement suggestions that will have a significant impact on this manufacturing system. Explain why?

Answer 1

Sand Casting One Molling Operation I Sand blasting Orinding I Cooting | Dogory NoHk Quality Cheek | Assembly Nota en LOK Frashed Product

Question no "a" ref attached image

For "b"

Improvement no 1

Quality Checking should be in each process

In existing process quality checking is present after almost the entire process completion. The quality of product should be checked in each process it will eliminate the possibility of bulk rejection in the final stage.It will save the 4M's of the manufacturing system. In every process starting station there should be on Stage inspector has to verify the initial out come of the part. Based on his inspection report only further production has to done.it will eliminate investigation done in after assembling the parts. it reduces the rework cost

Improvement no 2

FIFO need to follow up in every process

in existing process flow there is no mentioning in first in first out

Jobs are getting placed by batch in current process. FIFO followed means there is stagnation of job getting lagged between stations. It will help in clearing the inventory also