Blister Defects and Remedies in Pharmaceutical

Blister Film is a plastic processing technique that involves heating a flat plastic sheet, applying a vacuum to mold a surface, and then cooling the mold before filling it. This technique is widely used in plastic packaging, lighting, advertising, and decoration. However, issues related to the quality of blisters and defects in Pharmaceuticals may arise during the Blister formation process. These types of problems related to blister defects and remedies are explained below.

Blister Defects and Remedies:

Following are the issues that are encountered during the blister packing process:

Leak test failure

Wrinkle on Blister
Cavities Defects
Blister Cavity stuck in forming Plate

Forming station does not open fully
The camera system not working
PRC out of the bend

Pinhole detector not working Probable causes:
Homing not done
Blister Damage in sealing station

Motor overload
Emergency machine stop
Blister-dropping problem, machine not stared after pressing green button

Bend Blister or Twisted blister
Web direction uneven
Dott Impression on PVC/PVDC foil after pocket formation

Web slipping at the punching station
Low air Pressure
High-temperature cooling water

Thermocouple check/ perforation blade

1. Leak test Failure:

Probable causes	Suggested Action
Improper sealing due to less pressure	Maintain sealing pressure up to 5 bar
Sealing temperature less than required	Maintain sealing temperature as per BPR
Ink or extra material deposition on sealing roller	Clean the sealing roller with a brash brush

2. Wrinkle on Blister

Probable causes	Suggested Action
Guide plate alignment with a counter-sealing roller is not proper	Align the guide plate properly with the counter-sealing roller
Aluminum foil unwinding pressure low	Increase the unwinding pressure to the required level
Guide roller is not perpendicular to the Front Plate	Check if the guide roller is not perpendicular and correct it.

3. Cavities Defects

Probable causes	Suggested Action
Air went partially closed in some area	Check vent, do clean it if required
Failure of heater	Check heater properly
Height differences between heating and forming station	Set heating and forming station height and level.

4. Blister Cavity is stuck in Developing Plate.

Probable causes	Suggested Action
Forming plate not sufficiently cleaned	Check the cooling system, and reduce the temperature if required
Ejection pins are stucks	Check ejection pin

5. Forming station does not open fully

Probable causes	Suggested Action
Maybe due to jamming in moving Plate	lubricate piller bearing
Servo motor coupling is loose, or rubber is worn out	clean if foreign particles are deposited in the sliding part, replace the rubber

6. The camera system not working

Probable causes	Suggested Action
Signal or disconnection camera system	Check the signal coming from a camera
Camera key in special function is not activated	Activate camera key in a special function

7. PRC out of the bend

Probable causes	Suggested Action
Eye mark shifted while the machine running	Teach the PRC scanner
Distance between two eye marks on foil is not as per drawing.	check the distance between two eye mark.

8. Pinhole detector not working Probable causes:

Probable causes	Suggested Action
Input in PLC is not connected	Connect pinhole detector
Distance between pinhole and rejection system is not proper	Input right distance between pinhole and rejection system

9. Homing not done

Probable causes	Suggested Action
Homing is not performed	Perform homing of all axis

10. Blister Damage in a Sealing station

Probable causes	Suggested Action
PRC setting is not proper	Set the PRC
Improper sealing station knob tightness	Fixed the sealing station

11. Motor overload

Probable causes	Suggested Action
Motor is overheated	-Eliminate the error, wait until the motor has cooled down -Check the mechanical parts for roughness and blockage -Clean the drive unit -Lubricate the moving part

12. Emergency machine stop

Probable causes	Suggested Action
An emergency push-button activated	Unlock the emergency knob by turning it.

13. Blister dropping problem, machine not started after pressing Green button.

Probable causes	Suggested Action
Splice sensor	-Change the number of tracks selected in the PLC after the changeover. -Check the splice sensor, whether it is loose or not -Do the challenge test for PVC sensor and Alu splice

14. Bend Blister or Twisted blister

Probable causes	Suggested Action
Guiding roller before the indexing roller	Use the guiding roller having a diameter of 5mm less than blister width, for example, blister having 110x45mm which is 110mm in length and 45mm in width then, use the guiding roller having a diameter of 40mm. (45mm width-5mm=40mm) to prevent bend blisters.

15. Web direction uneven

Probable causes	Suggested Action
Forming plate	Check the lower forming plate position, tight the lower screw

16. Dott Impression on PVC/PVDC foil after pocket formation

Probable causes	Suggested Action
Heating plate surface	Use the heating tap on the identified surface from which impression generated

17. Web slipping at punching station

Probable causes	Suggested Action
Incomplete forming cavities, wrong blister setting in indexing roller	Remove the web from punching and check causes
Improper pickup	Check pickup assembly for any damaged vacuum pipe, tight their nuts, Check Vaccum.
Misalignment of support plate in punching plate	Align The plate as per blister size

18. Low Air Pressure

Probable causes	Suggested Action
-No compressed air, leakage in the air pressure line -pressure seal defective or set incorrectly -Faulty setting pressure regulator -Wire break in cabling in air pressure controller	Activate the compressed air supply, check the pressure gauge or maintenance unit

19. High-temperature of cooling water

Probable causes	Suggested Action
Thermocouple for cooling water is not connected	Connect the thermocouple, replace the defective one

20. Thermocouple check/ perforation blade

Probable causes	Suggested Action
Actual pressure of thermocouple blade is below 50°C	-Check thermocouple connection -Replace the defective thermocouple -Set the perforation blade temperature above 50°C

Conclusion:

The quality of the blister depends on the material and machine setting as per the given parameters. But sometimes, small problems can lead to harm to the quality of products. So, hope topics related to blister defects and remedies are covered all these problems.

Naresh Bhakar (Author)

Naresh Bhakar is the Founder and Author at Pharmaguddu.com, bringing his extensive expertise in the field of pharmaceuticals to readers worldwide. He has exprience in Pharma manufactring and worked with top Pharmaceuticals. He has rich knowledge and provides valuable insights and data through his articles and content on Pharmaguddu.com. For further inquiries or collaborations, please don't hesitate to reach out via email at [email protected].

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