Breaker Plate Technology, Part 2
| In this month's Technology Bulletin, we continue our look at Breaker Plate Design. In a recent investigation of an original equipment breaker plate, we calculated that a back pressure of 7000 PSI would be created if operated at full output! The first installment showed how to calculated " Dead Space " in the breaker plate. This issue shows how to calculate the back pressure generated using a simple fluid dynamic equation, the " Hagen Poiseulle Equation " for fluid flow in a tube. | |
BREAKER PLATE TROUBLE SHOOTING TABLE
| PROBLEM * | CAUSE * | SOLUTION | QUICK FIX |
| Resin degradation | Breaker
plate creates too much back pressure
leading to excessive shear heating |
Increase hole size in breaker plate | Use lesser screen pack |
| Particles of degraded resin in extrudate | Excessive dead space in breaker plate | Reduce breaker plate dead space | Chamfer inlet and outlet of breaker holes |
| Screen pack caked with degraded material | Poor breaker plate design with excessive dead space | Reduce breaker plate dead space | Chamfer inlet and outlet of breaker holes |
| Can't obtain design output for screw size | Breaker plate is too restrictive to resin flow | Increase hole size in breaker plate | Use lesser screen pack |
| High screw and barrel wear | Breaker plate causes too much back pressure | Increase hole size in breaker plate | Use lesser screen pack |
| High drive Amps | Breaker plate is too restrictive to resin flow | Increase hole size in breaker plate | Use lesser screen pack |
| High pressure drop from barrel to die | Breaker plate causes too much back pressure | Increase hole size in breaker plate | Use lesser screen pack |
| Leaks from breaker plate | Breaker plate causes too much back pressure | Increase hole size in breaker plate | Use lesser screen pack |
| Unstable barrel pressure | Not enough back pressure | Reduce hole size in breaker plate | Use greater screen pack |
| Non homogeneous melt | Inadequate screw plastication | Reduce hole size in breaker plate | Use greater screen pack |
* NOTE: This table assumes breaker plate to be root cause of problem. Carter and Associates are at (510) 490 7407 or fax (510) 490 3783