Surface Conductive Multilayered Sheet Burr Suppression
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Solution Overview
Problem
The miniaturization of electronic components has led to issues with flash and burrs during slitting and punching processes in carrier tapes, which existing thermoplastic resin sheets fail to adequately address across various forming apparatuses and resin types.
Innovation Solution
A surface-conductive multilayered sheet with 10 to 50 laminated layers of thermoplastic resin A and a conductive layer containing 65 to 95% thermoplastic resin B and 5 to 35% carbon black on one or both sides, specifically using polystyrenic, ABS, polyester, or polycarbonate resins, to minimize burr occurrence and enhance mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional thermoplastic resin sheets are used for carrier tapes, then the sheets can be easily manufactured and processed, but flash and burrs occur during slitting and punching processes
Solution Approach 1:
The substrate layer is divided into multiple thin layers (10-50 layers) laminated together, with each layer being 2-50 μm thick. This segmentation allows the total thickness to be maintained while reducing burr length, as burrs form at layer boundaries and cannot extend through the entire thickness. The conductive layer is also segmented into discrete regions between protruding portions, reducing overall carbon black content while maintaining ESD protection where needed.
Solution Approach 2:
The invention uses a composite structure combining multiple thermoplastic resin layers (substrate layer) with a conductive layer containing carbon black. This composite material approach allows the substrate to provide mechanical strength and processability while the conductive layer provides ESD protection. The multi-layer construction with specific resin combinations optimizes both burr suppression and electrical conductivity properties.
2Reliability
If carbon black is added to the surface layer to achieve conductivity, then static electricity prevention is improved, but the sheet becomes more susceptible to flash and burr formation during processing
Solution Approach 1:
The conductive layer containing carbon black is positioned only in specific regions between the protruding portions of the embossed pattern, rather than uniformly across the entire surface. This local placement provides ESD protection at critical areas while reducing the overall carbon black content that would otherwise increase flash and burr formation during processing. The substrate layer maintains its full thickness without carbon black interference in areas where conductivity is not immediately required.
Solution Approach 2:
The conductive layer is segmented into discrete regions separated by the protruding portions of the embossed pattern. This segmentation reduces the continuous carbon black network that would otherwise act as a pathway for flash propagation during processing. The multi-layer substrate structure also segments the potential burr paths, limiting their extension.
3Manufacturing precision
If the substrate layer thickness is increased to reduce burr occurrence, then burr length is reduced, but the mechanical properties and processability deteriorate
Solution Approach 1:
Instead of using a single thick layer, the substrate is divided into 10-50 thinner layers laminated together, with each layer being 2-50 μm thick. This segmentation achieves the same total thickness (maintaining mechanical strength) while limiting burr extension to individual layer boundaries. The multiple interfaces between layers act as barriers to burr propagation without sacrificing the overall structural integrity provided by the cumulative thickness.
Solution Approach 2:
The multi-layer substrate structure creates a composite material system where each thin layer contributes to the overall mechanical properties. The lamination of multiple layers provides both the thickness needed for burr suppression and the distributed structural strength, overcoming the limitations of single-layer designs. The interface between layers provides additional resistance to burr formation while maintaining flexibility and processability.
Data Source
Figure 1
AI summary
The present invention provides a surface conductive thermoplastic resin sheet and a molded member, such as an embossed carrier tape, using the sheet, in which burr- and flash-related faults are prevented, whatever the molding equipment, by a slitting method or punching when embossing. Provided is a conductive multilayered sheet, and an electronic component package, a carrier tape and a tray consisting of the conductive multilayered sheet, wherein respective layers with a mean thickness of 2 to 50 µm are composed of a thermoplastic resin (A), or a resin composition having the thermoplastic resin (A) as a main component, and wherein a conductive resin layer consisting of 65 to 95 wt% of a thermoplastic resin (B), or a resin composition having the thermoplastic resin (B) as a main component, and 5 to 35 wt% of carbon black, on one side or both sides of the base sheet consisting of multiple layers wherein 10 to 50 respective layers are layered.