Compression machines are used in the pharmaceutical industry to compress the powder or granules into tablets. Compression machines have different components, and cams are one of the most important parts of a tablet press.
Cam is also known as the cam track or punch track, which regulates and controls the movement of punches during the tablet compression process. The circular, up-and-down movements of punches are regulated by the different cams installed on the compression machine.
Functions of the Cams
The cams are helpful to perform the following functions
- Die filling
- Tablet weight regulation
- Tablet ejection
Types of Cams
The following are different types of compression machine cams,
- Upper Punch Removal/Insertion Cam
- Fill Cam
- Dosing Cam
- Upper punch lowering cam
- Upper punch pull-up cam
- Ejection Cam
Upper Punch Removal/Insertion Cam
Upper punch removal cam is also known as upper punch insertion cam or dwell cam.
This cam is used to insert and remove upper punches in the punch holders of the turret.
When this cam is removed, installed punches are removed and in case of insertion of punches, the cam is locked in place after insertion of all punches.
The Dwell Cam is positioned exactly above the feeder.
The dwell cam is also used to measure the tightness of the upper punches in the turret holders & for this, a spring-loaded cam is used, which raises the punches about 1 to 4 mm, and this cam is attached with a sensor.
When the punch tightness is observed, this cam falls down and cuts off from the sensor, so the machine is stopped.
Fill Cam
Fill cam is also known as a lower punches pull down cam because it pulls the lower punches down in the die bore and gives maximum space for filling of powders or granules.
Due to the pull-down cam, the lower punch in the die bore is lowered at its lowest position and powder or granules are overfilled.
Different sizes of fill cams are available & you can install the right cam as per product bulk density.
Dosing Cam
After passing through the fill cam, the lower punch passes over the dosing cam, which maintains the required level of product in the due bore after scraping.
The pull-down cam ensures die over-filling & dosing cam acts as a precise slope at which the lower punch rides & maintains a constant weight of powder or granules in the die bore.
Upper punch lowering cam
The upper punch lowering cam aim is to pull down the upper punches & lower the upper punches in the die cavity before compression. It also ensures proper punch penetration.
Upper punch pull-up cam
The function of the upper punch pull-up cam is to remove the upper punches from the die bore after compression.
After compression, the upper punches enter the upper punch pull-up cam to facilitate the ejection of tablets from the die bore.
Ejection Cam
The last cam of the compression cycle is the tablet ejection cam, and its function is to lift the lower punches into the die bore to remove the tablets from the die cavity.
When the upper punch is removed from the die, the lower punch rides over the tablet ejection cam & it is pushed upward to remove the tablet from the die cavity.
MOC of Cams
Cams are made of the following materials
- Steel
- Bronze
- Alloy
- Polymer
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