Improving Processing of Rubber in Injection, Transfer and Compression Molding Process

Transcription

1 Improving Processing of Rubber in Injection, Transfer and Compression Molding Process Acrolab Ltd. Windsor Ontario Canada

2 Introduction Mold heating time is the biggest contributor to the overall cycle time in almost all rubber molding applications Many molders fail to claim additional savings that can be achieved through optimized heating process 2

3 Molding Process Mold heating generally accounts for more than two thirds of total cycle time Open & Eject 6% Close 3% Fill 11% Heating 51% Pack & Hold 29% 3

4 Benefits of Optimum Heating Process Temperature Uniformity Reduced Residual Part Stress Cycle Time Reduction Scrap Rate Reduction Energy Savings Reduced Maintenance 4

5 Factors Affecting Mold Heating MOLD Material Thermal properties Part Geometry Thermal breaks between plates or inserts Location of Thermocouple Thermal properties Part Thickness Geometry RUBBER PART 5

6 Thermal Conductivity of Materials ISOBAR Steel Water Plastics RUBBER Air Material Aluminum Beryllium Copper Thermal Conductivity (W/m K) at 20 C , Factor **** 1.6x 3.7x 13x 650x 2,400x 2,600x 15,600x 6

7 Types of Isobars STANDARD FINNED STEPPED HOLLOW 7

8 Isobar - Function HEAT IN METAL WICK LIQUID FLOW HEAT OUT VAPOUR FLOW HEAT IN ISOBAR SHELL HEAT OUT 8

9 Isobar Function and Orientation VERTICAL HORIZONTAL / INCLINED HEAT OUT HEAT IN HEAT OUT HEAT IN HEAT INPUT MUST BE BELOW HEAT OUTPUT HEAT INPUT AND OUTPUT CAN BE ANYWHERE ALONG THE ISOBAR LENGTH 9

10 Isobars Passive Device Superthermal Conductors Thermal Uniformity of +/- 1 C Orientation Dependent Operating Temperature C 10

11 Thermal Performance of 25mm Diameter x 150mm Long Core CORE WITH ISOBAR CORE SOLID MOLDED PART CORE PIN ISOBAR HEATED MOLD PLATE HEATER 11

12 Thermal Performance of 25mm Diameter x 150mm Long Core Temperature (C) Steady State Steady State With Isobars Without Isobars Time (Minutes) 12

13 Thermal Performance of 25mm Diameter x 150mm Long Core Core Base Temperature (C) Core Top With Isobars Without Isobars Length (Cm) 13

14 Examples of Cores with Isobars ISOBAR CORE PIN 14

15 Isobar Design in Heated Cores TEMPERATURE UNIFORMITY OF HEATED CORE No Isobars With 4 Isobars Indirect Heating of Isobars 15

16 Isobar Design in Heated Cores ISOBAR 91.4 mm 16

17 Isobar Design in Transfer Molding Tree Bar Mold Core Pin Isobar Tree Bar Heater 17

18 Isobar Design in Heated Cores Epoxy Plug ISOBAR 18

19 Rubber Molding over Flat Plates 19

20 ISOPLATEN Bi-Level Matrix of Heaters and Isobars Acrolab Ltd. Copyright 2003 Introduction to Mold Cooling & Heating 20

21 STANDARD PLATEN 24 x 24 x 3 With 5 heaters Heaters ON Thermocouples 21

22 STANDARD PLATEN 24 x 24 x 3 With 5 heaters One Heater disconnected Heaters ON Heater OFF Thermocouples 22

23 HEATER TEMPERATURE PROFILE VS LENGTH 23

24 ISOPLATEN 24 x 24 x 3 With 5 Heaters With 13 Isobars 24

25 ISOPLATEN 24 x 24 x 3 With 5 Heaters With 13 Isobars One heater disconnected 25

26 Standard Platen Isoplaten Acrolab Ltd. Copyright 2003 Introduction to Mold Cooling & Heating 26

27 Isoplaten vs. Standard Platen Frequency ISOPLATEN Frequency Frequency ISOPLATEN 1 Heater Disconnected Frequency Temperature ( F) Temperature (F) Frequency STANDARD PLATEN Frequency Frequency STANDARD PLATEN 1 Heater Disconnected Frequency Temperature (F) Temperature (F) Acrolab Ltd. Copyright 2003 Introduction to Mold Cooling & Heating 27

28 Isoplaten vs Platen Consideration Thermal uniformity +/-2 C vs +/- 15 C Single Zone vs Multiple Zone Control 28

29 ISOPLATEN Mounting Holes Isobar Heater Thermocouple 29

30 ISOPLATEN T - Slots Isobar Heater Thermocouple 30

31 ISOPLATEN Center Hole Isobar Heater Thermocouple 31

32 ISOPLATEN Thermocouple Thermoswitch Isobar Heater 32

33 Rubber Molding of Automotive Gaskets EXAMPLE#1 33

34 Bottom Plate Isobar Heater 34

35 Top Plate with Isobars in Inserts Isobar Heater 35

36 Rubber Molding of Automotive Gaskets EXAMPLE#2 36

37 Top Cavity Plate Isobar Heater 37

38 Middle Cavity Plate Isobar Heater 38

39 Bottom Cavity Plate Isobar Heater 39

40 Rubber Molding of Automotive Seals Example#3 40

41 49 Cavity Injection Mold Isobar 41

42 Rubber Molding Tool Example#4 42

43 Single Cavity Tool Ø25mm X 7.5" LG. ISOBARS- 12 PCS STANDARD Ø25mm X 6.5" LG. ISOBARS- 15 PCS REVERSE 43

44 Thermoset Molding of Automotive Head Lamp Reflectors 44

45 2 Cavity Thermoset Head Lamp Reflector Mold Heater Isobar Thermocouple 45

46 2 Cavity Thermoset Head Lamp Reflector Mold Heater Isobar 46

47 Isobar Design in Head Lamp Molds Isobars shown Prior to Install Optic Surfaces Electrical Box Shown with heater Leads and T/C Mold Insulated 47

48 Isobar Design in Head Lamp Molds Cooling Isobars Heaters Heat Generation In mold Inserts 48

49 Isobar Design in Head Lamp Molds Heating Zone Electrical Box Heat Generation In mold Shoe 49

50 Isobar Design in Head Lamp Molds Heat Generation In mold Shoe With Isobars in Slides Slide with Isobars 50