Issue link: https://www.e-digitaleditions.com/i/1199406
Tablets & Capsules January 2020 17 Reduce the tamping pin diameter. Friction from the tamping pins entering and exiting the dosing disk can generate heat and cause sticking problems. To reduce the friction generated, you can try reducing the tamping pin diameter by one size. For example, if you are running size 00 tooling, try using size 0 tampers at the five tamping stations and the transfer station. Use plastic parts. Parts made of a lubricious, food- grade plastic, such as polyethylene terephthalate polyes- ter (PET-TX) can also reduce friction and minimize stick- ing problems. This plastic is internally lubricated with Teflon and is FDA approved. Many manufacturers have used dosing disks, transfer pins, tamping rings, and even bushed guide rings made of this plastic to successfully encapsulate the stickiest formulations. If all else fails If sticking problems persist after you've tried all the previous solutions, you may need to consider the fol- lowing options. Coat problematic parts. Using coated parts has proven effective in many cases, but it is relatively expen- sive and doesn't always resolve sticking issues. Typical parts that may benefit from coating include tamping pins, dosing disks, and segments. Common coatings include chromium nitride (CrN), zirconium nitride (ZrN), boron, and diamond-like carbon (DLC). Polish problematic parts. Another option to alleviate sticking is to polish problematic parts using micro/chem- ical polishing. This method uses a polish consisting of a fine, abrasive chemical to remove small peaks on critical surfaces, making the surface finish much smoother. It's recommended to have a professional complete this task or to receive proper training beforehand. While this pol- ishing method has proven effective, it can be expensive. Test new coatings and processes. Testing unproven methods can also be expensive, but manufacturers fac- ing a dire-enough sticking problem may be willing to try anything. Technology is advancing quickly, and coating and material options will surely be available in the not- too-distant future that may prove effective. Change the formulation. Adding a lubricant or a flow aid to the formulation may also help reduce stick- ing. However, developing a drug product formulation is costly and time consuming, so even small changes can seem daunting. As a result, manufacturers are typically reluctant to consider changing their formulation to reduce sticking until they've exhausted all other solutions. Sticking problems are common in encapsulation pro- cesses, and there is no one-size-fits-all solution. Often a combination of solutions is required. Following the sugges- tions discussed in this article will help to eliminate many of the common root causes of sticking and increase your odds of successfully encapsulating sticky formulations. T&C Jon Carlisle is the founder of Carlisle Precision Encapsulation Parts, a subsidiary of Natoli Engineering (636 926 8900, www.natoli.com). The company is a leading manufacturer of aftermarket change and spare parts for encapsulation machines. Photo 4: Coating problematic parts may alleviate sticking in some cases, but coatings such as the diamond-like carbon coating shown here are relatively expensive and do not always eliminate the problem. The best lifts at the lowest prices! Fast, reliable, high tech Post drum lifts for your tablet press or capsule filler. Simple, fool proof operation. Easy setup. Easy installation. Quick delivery. All Stainless steel and sanitary design. Post provides 3D designed stack ups of any combination of drum, bin or bag lift, sifter, blender, mill, weigh out system, powder chute and access platform all with one integrated control system in a turnkey package. www.posthoist.com/contact | 845-200-3355