การปรับปรุงคุณภาพการผลิตในบริษัทผลิตสายไฮดรอลิกทนแรงดันสูง

Abstract

This research is focused on quality improvement project in high pressure hydraulic hose manufacturing company. In the stage of problem identification, the most crucial problem that is needed to be fixed is hose swelling. It is recognized since the production data is analyzed and illustrated the stability pattern. Thus this swelling problem is predictable how lost from this kind of defect the company does. And if it is still neglected to work out and to eliminate the root cause, it will be recurred in the near future. Under observation, hose swelling always exists in the production process of braiding department, which consists of two stages. They are freezing process and braiding process by the use of freezing and braiding machine, respectively. From function analysis of braiding process, it is found out that inner rubber of hydraulic hose must be solid enough to be able to endure the tension force from braiding machine. Solid state of inner rubber can be affected from freezing process. By investigating quality planning of braiding process, wires will be braided on inner rubber of hydraulic hose, and when the wires run out, the machine will be stopped. This will make the temperature of hydraulic hose, which is between freezing and wire-braiding machine, highly increases. When wire-braiding process is restarted, the hose that lost temperature will encounter with the swelling problem. Therefore, the project team members brought up the concept in order to reduce swelling defects. Counter is installed for warning operators before the braiding wires run out. And the appropriate length of wire and hose is calculated and converted to braiding cycle time, which will be set on counter. When the setting time reaches, the operators will be warned to prepare in order to cut and connect hose with bare mandrel. Thus the wires will be braided on mandrel and hose swelling will not be occurred.