Don’t Lose Your Head: The “Punch Head”
The punch head’s importance in tablet production, and role in tablet quality
When inspecting a tablet compression tool (Punch) it’s common to check dimensions such as overall length, cup depth and working length. One commonly overlooked component of the tool during inspections is the “head” of the tool. Checking the punch head for wear can improve tablet quality and reduce cost for your organization.
Make-up of a punch head
The Inside Head Angle– This is the part of the punch that rides on the ledge of the cam. This part of the tool is commonly damaged when tools cams are out of alignment, tools bind or from improper lubrication. When using steel cams, misalignment will cause excessive wear and gouging to the inside head angle of the punch. If caught early enough, the tool can be repaired by buffing on a polishing machine. If not repaired properly, tool damage will worsen and ultimately damage the Pull Down or Lifting Cams of the tablet press. If you are running bronze cams, the cams will prematurely wear – creating unwanted costs in replacement parts and unnecessary down time.
Outside Head Angle/Radius– The part of the tool that first comes in contact with the pressure rolls. Damage to this location can result in damage to the pressure rolls and result in the production of inconsistent tablets.
Head Flat– The flat spot located on the very top of the punch. It’s this area of the tool that determines your “dwell time” (in conjunction with turret RPM’s and Pressure Roller diameter.) Head flats that are found to be elongated (larger than the punch neck) may lead to tool breakage and excessive/costly damage to the tablet press.
Inspect tools through “Go/No-Go Gauge”
After performing a visual inspection on these areas, the quickest and easiest way to inspect new and in process tools is to run the Heads through a “Go/No-Go Gauge.” This inexpensive tool shows if your head angles and head flat are consistent and acceptable for use with the current cams in your press (either EU or TSM). Checking the punch head for wear and other defects will ensure that you receive consistent tablets, and that your tooling will perform well over time.