2. A bone...

3. TEM P LATE Bao-Yi ChangElissa Robbins Elizabeth ImmenLisa Scoppettuolo 3.082 FINAL PRESENTATION May 17, 2001

4. Injection Molding Thank you to Speed of Light for the Casting photograph

5. www.biomet.com

6. Iron or Stainless Steel Polymers: PLLA or PCL

7. To fabricate a bioresorbable bone plate To fabricate a bone plate with a modulus close to that of bone through selection of materials and processing conditions Mission/Goals

8. Injection Molding Used to fabricate plastic objects -CD cases, water bottles, toys Easy one step process Ideal for mass production

9. Injection Molding Machine Battenfeld 250 Mold Chamber Hopper Plasticating Unit Control System Equipment Specifications

10. Injection Mold Process 2. End Plastication 3. Close Mold 4. Begin Injection Mold 5. Eject Part 1. Begin Plastication screw nozzle

11. Mold -Obtaining Mold Blank -Design Process -Machining -Adjustments Plate Dimensions(in)

12. Experimental Runs Establishing Ideal IM Conditions Varying Parameters Product Testing….

13. Instron Tensile Testing

14. Results: Instron Testing

15. IM1: low screw speed, low pressure IM Parameters  Mechanics Bone plate, not shaped for tensile testing IM2: low screw speed, high pressure IM3: high screw speed, low pressure IM4: high screw speed, high pressure

16. Gel Permeation Chromatography PCL degrades by hydrolysis PCL was placed in water to simulate the body’s aqueous environment Hydrolytic cleavage of PCL chains  Decrease in molecular weight

17. Polymers with low melting points are typically: low molecular weight T m  Mw Differential Scanning Calorimetry Melting point of PCL = 63.245 o C

18. Decision Tree

19. Bioglass Fibers Ceramic Particles: - Hydroxyapatite -  -tricalcium phosphate Fabricate bone plate from a completely bioresorbable COMPOSITE - Satisfy the mechanical requirements of bone plates - Mechanically superior to many bioresorbable homopolymers... Further Work and Study Future Plans Possible Reinforcers  -tricalcium phosphate (Ca 3 (PO 4 ) 2,  -TCP) is a bioresorbable ceramic

20. FTIR patterns of PDLLA, TCP, and a PDDLA/TCP composite (50 wt. % TCP) Poor adhesion between polymer matrix and ceramic reinforcer Poor mechanical properties Possible Problems :

21. - Melting and Hot Pressing - Twin Screw Extrusion - Pelletize Composite Mixture - Injection Molding: Viscosity (  ) is an important parameter Methods of fabricating a PCL/  -TCP bone plate:

22. “To fabricate a bone plate with a modulus of 3 GPa, the composite would have to be 90 % TCP by volume!” E composite = X TCP E TCP + (1-X TCP )E PCL (upper bound) E composite = 1 / [(X TCP / E TCP ) + (1-X TCP )/ E PCL ] (lower bound) Source: Ashby, M. Engineering Materials I. Feasibility of a PCL/  -TCP Composite

23. TemPlate’s Composite Bone Plate By hot pressing a composite material of volume fraction 90% PCL / 10%  -TCP, the modulus was increased by 60%.

24. Cost Analysis

25. $Purchase Mold: (Master Unit Die) = $400 $Design ($60/hr * 30hr) = $1800 $Machining ($52/hr * 35hr) = $1820 ---------- Total for Mold $4060 Polymer Injection Molding

26. Cost Analysis

27. Processing Cost Analysis $Battenfeld Machine Repair = $250 $Optimizing Initial Processing Conditions ($60/hr * 6hr) =$360 $Injection Molding 1000 plates ($60/hr * 40hr) = $2400 ---------- Total for IM $3010

28. Cost Analysis

29. $Polycaprolactone (Polysciences, Inc. ($200/kg*20kg) = $4000 Cost Analysis Material

30. $Mechanical testing (Instron) ($60/hr*10hr) = $600 Product Analysis Cost Analysis

31. $Overhead~ $7000 $Mold = $4060 $Injection Molding = $3010 $Materials = $4000 $Product Analysis= $ 600 Summary Cost Analysis = $18,670 --------------- Total Cost of 1000 bone plates

32. Cost Analysis $20/bone plate *Biomet.com competition * $168/bone plate