The creation of tooling using the selective laser sintering process. Scott Schermer S.C. Johnson

Transcription

1 The creation of tooling using the selective laser sintering process Scott Schermer S.C. Johnson 1

2 TOOLING utilizing traditional rapid prototyping machines to produce metal inserts. 2

3 LaserForm ST-100? Used to create solids in the Selective Laser Sintering Process 420 stainless steel powder (d 50 = 23 microns ) Sintered then Infiltrated with commercial bronze (89% copper/11% tin) 3

4 Future Moldmaking Technology / Tool OR Curious Fad??? 4

5 We are at the beginning of a very powerful and exciting technology. Looking back at other technologies and their beginnings helps to show where the SLS technology is today. 5

6 Early Beginnings Looking at the early NC machines Skeptics did not believe it would survive or flourish for tool making applications. After all, it was not accurate enough, fast enough, and did not have enough power. Early critics did concede that it might be useful for machining of pockets or simple shapes. 6

7 Early Beginnings The same could be said for early EDM machines. Why go through the trouble and time of machining electrodes and then taking the time to burn the electrodes into the steel? After all, the EDM process was the slowest of all machining practices. 7

8 Early beginnings As we all know now both of these technologies are extremely powerful, no modern mold can be manufactured today without either of these technologies. No mold builder is without either piece of equipment. 8

9 The current SLS technology, as it applies to tool making, is a powerful tool if used correctly. It has the potential to impact the tooling industry as we know it today. 9

10 CAD file preparation Selective Laser Sintering (SLS) processing Furnace processing Mold finishing/mold preparation Mold repair Molding 10

11 Process Solid model (CAD file) of mold is required. Model is sliced into layers using slicing software. Add machining stock to all areas that will require additional machining. 11

12 SLS Processing Load Parts or Tools Scale and Offset for Process Push start Remove Parts when process is complete Build Rate 7 Hours per 25mm of build height based on a solid block 250mm x 200mm(10 x 8 ) 12

13 13

14 Breakout Handling green parts Tools Compressed Air bar (5-15psi ) Soft Art Brushes Lapping tooling inserts 14

15 Oven Process Weigh parts Load crucible Load Oven Push Start Total Time Setup time 1/2 hour Oven Cycle 24 hours 15

16 Oven Cycle Sintering and infiltration at 1070º C Tab infiltrant delivery method Parts buried in fine Alumina powder 16

17 Weigh green part and tabs to calculate bronze needed. Place part in the crucible on an Alumina Plate. Add tabs & bronze. Add alumina powder, cover crucible and place in oven 17

18 Post Processing Remove from Furnace Remove from Crucible Mold Finishing Square tool Machine parting lines Polish to desired finish 18

19 Machining Grind, Mill, Drill, Wire Cut, EDM, Texture Welding & Brazing Polishing Standard polishing techniques apply Plating Chrome, Nickel, etc. 19

20 20

21 21

22 22

23 Material Properties Stainless steel-bronze (60%/40%) composite Type 420 stainless steel (d 50 = 23 microns ) Thermoplastic/Thermoset binder (2.75 wt %) Commercial bronze (89% copper/11% tin) Mechanical Properties Hardness Rockwell B High wear resistance Twice the thermal conductivity of H13 and 420 stainless 23

24 Comparison to R.S.2 Faster Process One furnace cycle Optimized SLS process Improved Machinability 420 Stainless Steel Softer material Decreased Cost No Hydrogen Process Time Reduced Oven 24

25 Applications Type of geometry of molded part. Function of part. Dimensional accuracy molded part. All of the above play a part in determining if SLS will be a useful tool in the manufacturing of mold inserts. 25

26 Get toolmakers onboard upfront Get them educated on the technologies 26

27 It is important to remember, this is only a tool When used correctly it is very powerful Used incorrectly it is ineffective 27

28 It s easy to get caught up in the magic and lose sight of RT s true role. Design process should focus on the end-product, not on the technology used to create it. 28

29 You are limited only by your skill and knowledge of tooling NOT the technology 29