|Excessive Metal Velocity|
If metal exits the runners from the cavity to the Valve-Less Block with excessive velocity, it can washout the steel of the critical flow area and result in sticking. Midland recommends a minimum of five 90 degree turns in the vacuum or vent runners before reaching the inlet of the Valve-Less Block(s). Midland will provide a recommended vacuum block runner layout free of charge for any die using Midland Valve-Less Vacuum Blocks.
|Damaged Block||It is recommended to periodically check the critical flow area of Valve-Less Blocks in order to ensure that there is no damage to the teeth. Pits, nicks, and broken teeth can result in sticking. If the block appears damaged, remove and replace with a new block.|
|Metal Solder||In the event that metal is soldering to the Valve-Less Blocks, it is recommend that the cooling lines be utilized and/or release agent be sprayed on the area that is sticking.|
Additionally, Midland’s Variable Pattern for Valve-Less Vacuum Blocks helps to reduce sticking issues which can occur depending on the alloy, process, and environmental factors. You can find information about the Variable Pattern at http://www.valuemoldcomponents.com/midland/index.php/variable-geometry.