Fill cam selection in tablet press is critical step of achieving the final weight of the tablet during compression process specially for new product.
The manufacturing of tablets is a process that faces many difficulties, and an understanding of the processes that lead to the final, compressed tablet is vital in the process of creating the best quality tablet.
The most important factor in ensuring the quality of a tablet that meets acceptable characteristics is the final weight of the tablet. The weight of the tablet is not solely influenced by the amount of active ingredient but also directly influences the compression force applied which in turn affects the tablet’s strength friability, strength, disintegration and dissolution time.
Fill cam selection in tablet press
The fill cam is a lower cam located under the feeder and it use to overfills the cavity of the die. The next cam to the fill cam is the dosing cam that will remove excess material in order to attain the desired weight. The excess powder is scrap out using the scraper bar, which then will direct the powder towards recirculation area of turret. the recycling route to be returned back to the feeder.
[Fill cam selection in tablet press]
It is essential to be aware that the correct fill cam size needs to be chosen based on the position of the dosing cam. The suggested overfill is 2-4mm. The size of the fill cam can be estimated by calculating the dosing-cam depth in order to attain the desired weight, and then adding the 2-4mm. Dosing cams are built on the tooling geometry, bulk density of the material and the tablet’s weight. The first step is to calculate the amount of powder that will be compressed, by multiplying tablet’s final mass by bulk density.
Tablet press Fill cam selection formula
Compression machine fill cam calculation formula, First calculate required Filling depth by using following formula :
h = W / [ (D)2 x π/4].ρ
Where, h = Filling depth (mm)
W = Standard Tablet weight (mg)
D = Punch surface (mm)2 for round shape punch. Calculate Punch surface for capsule share punch = Length x width.
ρ = Bulk density
Recommended Fill cam = h + 2 mm.
A fill cam should be 1-2 mm larger than the actual fill depth in order to minimize the variation in weight and loss of product. For instance suppose estimated fill depth is 10 mm than, you’d pick the 12 mm fill cam.
Fill cam selection in compression machine example
How to select Fill cam of the product for example paracetamol 500 mg during compression machine.
First calculate required Filling depth by using following formula :
h = W / [ (D)2 x π/4].ρ
W = Tablet weight (mg). here for example Tablet weight of paracetamol 500 mg, W = 650 mg.
D = Punch surface (mm)2 = (Length x width) = (16*8) =128 mm2
π/4 = 3.14/4 = 0.785
ρ = Bulk density, here for example Bulk density of paracetamol 500 mg blend is, ρ = 0.55 g/mL
h = Filling depth (mm) = W / [ (D)2 x π/4].ρ = 650/128*0.785*0.5 = 650/55 = 11.82 mm
Recommended Fill cam = h + 2 mm = 12 + 2 mm = 14 mm.
Types of cam in compression machine
Compression machines have different types of cams for example :
- Upper Cam
- Lower Cam
- Fill Cam
- Dosing Cam
- Ejection Cam
- Anti-flight Cam
Fill cam size
Most commonly used Fill cam size are 8 mm, 10 mm, 12 mm, 14 mm, 16 mm.
FAQ | Fill cam selection in tablet press
What is fill cam in compression machine?
Fill cam is a an essential component of the tablet press, also called “pull down” cam. Tablet press operates on the concept of overfill. the overfill can be achieved by with the help of fill cams to lower the lower punch, allowing for the press to be filled with with excess blend. The selection of the right fill cam is essential to ensure the proper operation of the machine.
How do I select a fill cam?
It is crucial to understand that the appropriate fill cam size must be determined based on the position of the dosing cam. The size of the filling cam is approximated by taking the depth of the dosing cam to reach the weight you want and then adding 2 mm. The suggested overfill is 2 mm.
What is the formula for fill cam?
How do you select a fill cam for a new product?
First calculate the required fill depth for new product by using ‘Tablet weight /Punch surface area * Bulk density’ formula. then adding 2 mm suggested overfill.