Adding Keypads and Cables to Your Injection-Molded Enclosure
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The document discusses manufacturing processes for creating custom injection-molded enclosures with a focus on keypads and cabling solutions to enhance reliability and reduce risks. It provides insights into material selection, prototyping, ingress protection, and design considerations for electronic assemblies. Key recommendations include the use of 3D printing for prototyping, understanding certifications, and the importance of guarding against environmental ingress.
Adding Keypads and Cables to Your Injection-Molded Enclosure
- 1. Manufacturing That Eliminates Risk & Improves Reliability Adding Keypads and Cables to Your Injection-Molded Enclosure 08.18.23
- 2. Manufacturing That Eliminates Risk & Improves Reliability 2 Agenda Enclosure Materials and Options Keypad and Cabling Considerations for Enclosures Ingress Protection & Shielding Examples and Design Solutions How To Get Started With Your Custom Build
- 3. Manufacturing That Eliminates Risk & Improves Reliability 3 Enclosure Materials and Options
- 4. Manufacturing That Eliminates Risk & Improves Reliability 4 Injection Molding with Thermoplastics Why Injection Molding? Types of Products – Box-builds with PCBAs – Test apparatus – Industrial control equipment Most common materials – ABS/PC/PP/PE – Brand names and equivalent materials • Covestro, Sabic Top and Bottom Enclosure Lids
- 5. Manufacturing That Eliminates Risk & Improves Reliability 5 Injection Molding with Thermoplastics Benefits – High strength to weight – Low cost – UL-recognized materials – Flammability Additional considerations – Solid modeling – .STP file is required – Hard tooling – Not appropriate for rapid proto Solid Model of Enclosure Concept FEA Stress Analysis
- 6. Manufacturing That Eliminates Risk & Improves Reliability 6 When to Use 3D Printed Enclosures ? Early and often Inexpensive and readily available Additive manufacturing process – No hard tooling Common materials – PLA filament – PC, ABS, Nylon For 3D printing, the cosmetics and surface finish will differ from inj molding
- 7. Manufacturing That Eliminates Risk & Improves Reliability 7 Prototyping Silicone Elastomers Keypads, gaskets, grommets 3D printing “rubber” is an option – Does not behave like silicone elastomer Ideal for agile methodology – Reduce risk for necessary material changes Consider hobbyist materials – Under $100 in materials – A few days’ samples can be molded Still need to design and 3D print a mold
- 8. Manufacturing That Eliminates Risk & Improves Reliability 8 Keypad Considerations for Enclosures
- 9. Manufacturing That Eliminates Risk & Improves Reliability 9 Membrane Switch & Keypad Options Membrane Switches – A momentary switch device in which at least one contact is on, or made of, a flexible substrate- ASTM – LEDs, dome switches, and adhesive Silicone Rubber Keypads – Compression-molded silicone elastomer – 40-60 Shore A hardness – Pair with dome switch or conductive carbon pill High-Reliability & Low Cost LEDs for Backlighting – LED windows – Uniform backlighting Silicone Overlay With Circuit LED Locations
- 10. Manufacturing That Eliminates Risk & Improves Reliability 10 Keypad - How Does It Attach? Most keypads are affixed with only adhesive Use the brand name adhesives – 3M467, VHB Mechanical attachment – Backplate and fasteners – Thru holes Mounting Hole Locations
- 11. Manufacturing That Eliminates Risk & Improves Reliability 11 Routing the ZIF Tail Not all keypads use ZIF tails – Some use terminals + housing Enclosure must have recessed slot Keep the shape simple – Easier to define Route ZIF Tail Through Slot In Enclosure
- 12. Manufacturing That Eliminates Risk & Improves Reliability 12 Keypads - Backlighting Options LEDs are most common – 0603 is smallest package size Light pipes to illuminate key features Light Guide Film (LGF) Use Bi-Colored LEDs to Achieve Dual Color Backlighting
- 13. Manufacturing That Eliminates Risk & Improves Reliability 13 Cabling Considerations for Enclosures
- 14. Manufacturing That Eliminates Risk & Improves Reliability 14 Don’t Reinvent The Wheel What is the cable for? – Power - 120VAC, 28VDC – Data - USB, GPIO – Video - HDMI, Dsub9 Research existing off-the-shelf options Many have IP ratings and are UL-listed Cobble something together
- 15. Manufacturing That Eliminates Risk & Improves Reliability 15 Typical Conductor Design Options “Internal wiring of appliances” – Extremely common – Hook-up wire – Single-conductor – Multi-conductor Flammability ratings are critical Shielding options – Braided shield – Metalized foil – Drain wire Specifications – Voltage – Temperature – Jacket Thickness – Shielding – Flammability Materials – PVC – XLPE – PFTE – FEP – Silicone
- 16. Manufacturing That Eliminates Risk & Improves Reliability 16 Custom Extrusion Options Low Cost – Not available “off-the-shelf” – Must meet minimum order qty Complete Customization – +50 conductor cross-sections – Mix and match wire sizes – Vary the shielding Maintaining UL Compliance – Some customization may violate UL Non-UL Custom Extrusions Can Be Made In 3 Weeks
- 17. Manufacturing That Eliminates Risk & Improves Reliability 17 Adding Overmolds to UL Cables Overmold will not violate UL rating Primary overmolding concerns – Material compatibility – Flammability Additional levels of customization – Ruggedization – Adding artwork or logos House Tooling Is Readily Available With $0 NRE Expense Epec House Tooling M12 x 4 Pin Connector UL2517 Wire RJ45 Overmold Phono Plug Overmold
- 18. Manufacturing That Eliminates Risk & Improves Reliability 18 Ingress Protection & Shielding
- 19. Manufacturing That Eliminates Risk & Improves Reliability 19 EMI & Shielding Considerations Radiated Emissions and Susceptibility – Shielding must be added – LVDS cables, noisy components – PCBAs and keypads – Application Specific – Specifications • UL, CSA, EN, IEC • Federal Consumer Product Safety Commission • Medical IEC 60601 • Mil-aero MIL-STD-810, RTCA/DO-160, MIL-STD-461 Metallized Coating for EMI Shielding
- 20. Manufacturing That Eliminates Risk & Improves Reliability 20 Ingress Protection Water, dust, salt Sealing surfaces can be added to keypads Additional gasketing may be necessary Mechanical fasteners or adhesives are used Leak tests must be performed at system level to represent actual conditions 1mm Lip Sealing Surface Dust Contamination On Contacts
- 21. Manufacturing That Eliminates Risk & Improves Reliability 21 Understanding The Test Results Does ingress constitute a failure? Clear pass/fail criteria – Is system performance impacted? Isolate the sealing surfaces IP67 is a difficult test to pass
- 22. Manufacturing That Eliminates Risk & Improves Reliability 22 Examples and Design Solutions
- 23. Manufacturing That Eliminates Risk & Improves Reliability 23 Adding Cable Strain Relief How will the cable pass through the wall? Use an off-the-shelf cord grip Epec can recommend standard strain relief designs and shapes
- 24. Manufacturing That Eliminates Risk & Improves Reliability 24 Adding Cable Strain Relief Engineer the interface – Study the tolerances and process limitations Note critical dimensions and tolerances
- 25. Manufacturing That Eliminates Risk & Improves Reliability 25 Custom Strain Relief for Enclosures Size the Overmold to the Enclosure Slot
- 26. Manufacturing That Eliminates Risk & Improves Reliability 26 Keyboard with Rigid PCB - Ways to Mount Multilayer rigid PCBs – Include fasteners – Headers Off-the-shelf tactile switches Hard keycaps + silicone rubber Injection mold the keycaps – Pad print markings
- 27. Manufacturing That Eliminates Risk & Improves Reliability 27 Enclosure with SPST Switch & PCBA Use an off-the-shelf switch Develop way to mount switch Electrically connect to PCBA Need clearance to assemble
- 28. Manufacturing That Eliminates Risk & Improves Reliability 28 Heavy Duty Power Cable & Enclosure Indoor use only Drop testing EMI/EMC requirements Operate at 220VAC 30A
- 29. Manufacturing That Eliminates Risk & Improves Reliability 29 Heavy Duty Power Cable & Enclosure Ultrasonic welded lid Overmolded strain relief Enclosure slots for venting
- 30. Manufacturing That Eliminates Risk & Improves Reliability 30 How To Get Started With Your Custom Build
- 31. Manufacturing That Eliminates Risk & Improves Reliability 31 Taking the Design First Steps What industry and agency approvals? Where will this be sold? – Globally recognized – Additional testing required for Korea, Taiwan, South Africa, Chile, and Argentina Initial certification – Product safety – Environmental qualification Establish system requirements
- 32. Manufacturing That Eliminates Risk & Improves Reliability 32 Build Prototypes Before Initial Production It doesn’t have to be perfect There is a lot you can learn once built Use 3D Solid Modeling software Model every component and wire Partnership with one vendor helps reduce integration challenges Use Solid Modeling to flush out design issues Interference Between Standoffs and Rubber Keypad Webbing
- 33. Manufacturing That Eliminates Risk & Improves Reliability 33 Strategically Use 3D Printing Fast, inexpensive, and everywhere 3D printing is wildly helpful – It’s not the Holy Grail How many samples and when? – What testing is being performed? Understand the process limitations Be weary of test results using 3D printed members
- 34. Manufacturing That Eliminates Risk & Improves Reliability 34 Epec Inquiry Form When starting a project with Epec, we ask if you could please fill out our Inquiry Form This allows us to capture all the information of your design upfront, eliminating guess work Also allows us to provide you with an accurate quote
- 35. Manufacturing That Eliminates Risk & Improves Reliability 35 Technical Data & Development Budget are Required We require a statement of work Manufacturability assessment Performance requirements Where will this product be used? We create the engineering data Give Us The Requirements and We Will Figure Out How To Build It
- 36. Manufacturing That Eliminates Risk & Improves Reliability 36 Summary
- 37. Manufacturing That Eliminates Risk & Improves Reliability 37 Summary Plan for several rounds of prototypes for fit checks and testing Leverage readily available materials Add customization where it makes sense Spend time understanding ingress protection requirements Invest in development PCBAs for integration and beta testing Ultimate goal is to build production worthy samples as fast as possible
- 38. Manufacturing That Eliminates Risk & Improves Reliability 38 Our Products Battery Packs Flex & Rigid-Flex PCBs Cable Assemblies Printed Circuit Boards CNC Machining User Interfaces Flexible Heaters EC Fans & Motors
- 39. Manufacturing That Eliminates Risk & Improves Reliability 39 Q&A Questions? – Enter any questions you may have in the control panel – If we don’t have time to get to it, we will reply via email
- 40. Manufacturing That Eliminates Risk & Improves Reliability 40 Thank You Check out our website at www.epectec.com. For more information email sales@epectec.com. Stay Connected with Epec Engineered Technologies Follow us on our social media sites for continuous technical updates and information: