ApplicationsCure Silicon on Hose
Application:
A manufacturer of hoses preheating and curing silicone.
Problem:
- Slow Line Speed - The line speed was limited to 25 feet (7.6 meters) per minute with the existing resistant-type heaters that were used to preheat the raw, braided silicone.
- Slow Heat Up Rates - The high thermal mass of the existing resistance-type heaters prevented them from reaching operating temperature in an acceptable amount of time.
- Slow Cool Down Rates - Their high thermal mass also prevented the resistance-type heaters from cooling down quickly, which frequently resulted in fires when the line was suddenly shut down.
- Excessive Scrap - The uneven heating and poor control of the resistance-type heaters produced unacceptable amounts of bubbled hose that had to be scrapped.
Solution:
- Heat - Six Model 4069-12-25 Clamshell Heaters were used to apply heat to the silicone. Two of the heaters preheated the raw, braided silicone and four of them cured it after it had been extruded.
- Power Control - A Model 664 Phase Angle SCR Power Controller controlled the power to each Clamshell Heater.
- Process Management - A PLC and Color touchscreen were used to manage the four-zone cascade loop of the four heaters used to cure the silicone.
- Instant On/Off - The Clamshell Heaters heated up and cooled down instantly in response to signals received from the SCR Power Controllers.
Benefits:
- Increased Line Speed - By preheating and curing the silicone with the Model 4069 Clamshell Heaters, the manufacturer was able to increase line speeds by 220% to 80 feet (24.4 meters) per minute.
- Fast Heat Up Rates - The instant on/off capabilities Clamshell Heaters reduced start-up time for the line to seconds.
- Fast Cool Down Rates - The instant on/off capabilities of the Clamshell Heaters also enabled the line to stop instantly without causing fires.
- Reduced Scrap - The even heating provided by the Clamshell Heaters, combined with the precise control provided by the SCR Power Controllers and PLC Control produced a better surface finish on the hose and significantly reduced the manufacturer's scrap rate.