Connectors Grades of SUMIKASUPER LCP

Grade Selection Guide for Usage in Connectors

Properties Required by Connector Materials

The term "connector" includes a wide variety of components that are used for purposes such as: mounting LSI chips onto circuit boards; connecting cables to circuit boards; and providing interconnection between circuit boards. Connectors are increasingly becoming multipolar and further miniaturized, in keeping with recent trends toward the manufacture of advanced electronic devices that are smaller, thinner and lighter than ever before. Moreover, the primary means of mounting connectors is gradually shifting toward the use of Surface Mount Technology (SMT), in which connectors are soldered at a high temperature of 240-260˚C. For these reasons, SUMIKASUPER LCP products are often utilized, due to their high precision moldability and high heat resistant properties.

Figure 1 :
Mounting Defects Caused by Connector Warpage
Figure 1 : Mounting Defects Caused by Connector Warpage

However, the major shortcoming of SUMIKASUPER LCP is its high anisotropy. Connectors composed of SUMIKASUPER LCP are produced by the injection molding process. During production, the level of SUMIKASUPER LCP resin shrinkage within the mold is different in the resin flow direction (MD: Machine Direction) than the shrinkage that occurs perpendicularly (TD: Transverse Direction). This differential shrinkage leads to connector "warpage", which may subsequently cause defects when connectors are soldered during the SMT process (Figure 1).

Since SUMIKASUPER LCP is an anisotropic resin, it is difficult to mold without the addition of a filler. In order to reduce the degree of anisotropy, SUMIKASUPER LCP should be combined with a filler, such as glass fiber or inorganic filler. An important difference between SUMIKASUPER LCP and standard resins is that the addition of fillers to standard resins causes increased anisotropy, yet the addition of a filler, such as glass fiber, to SUMIKASUPER LCP actually reduces the degree of anisotropy.

Grade Selection Guide for Usage in Connectors

The connector guide for SUMIKASUPER LCP introduces SUMIKASUPER LCP products that incorporate fillers, such as glass fiber or inorganic filler. It is necessary to understand that the appropriate grade (with less warpage) may vary, depending upon the particular shape of the connector (especially depending upon the wall thickness of the molding).

  • DIMM sockets with relatively thick walls: E6006LHF and E6006LMR
  • Flat multipolar PGA sockets: E6807LHF and E6808LHF
  • Flat PCMCIA sockets with no holes or ribs, and card connectors for memory cards: E6810MR
  • Thin board-to-board connectors of reduced heights: E6008, E6808THF and E6808GHF
  • For fine pitch connecter: SZ6506HF

Figure 2 : Application of SUMIKASUPER LCP Grades for Usage in Connectors

Figure 2 : Application of SUMIKASUPER LCP Grades for Usage in Connectors

Physical Properties of Standard Grades
Table 2 shows the physical properties of our standard grades. The levels of warpage within the table have been evaluated using molds designed by our company. Therefore, there may be differences between these values and actual warpages (may be compared with our previous grades).

Table 2 : Standard Physical Properties of SUMIKASUPER LCP Grades for Usage in Connectors

Item Measuring
method
Unit E6007LHF E6807LHF E6808LHF E6808UHF E6810LHF E6810GHF
Filler - - Glss Fiber
(Chopped)
35 wt%
Glass Fiber/
Inorganic Filler
(Chopped)
35 wt%
Glass Fiber/
Inorganic Filler
(Chopped)
40wt%
Glass Fiber/
Inorganic Filler
(Chopped)
40wt%
Glass Fiber/
Inorganic Filler
(Chopped)
50 wt%
Glass Fiber/
Inorganic Filler
(Chopped)
50 wt%
Specific gravity ASTM D792 - 1.65 1.67 1.70 1.72 1.82 1.84
Mold shrinkage MD Sumitomo
Chemical
Method
% 0.20 0.11 0.17 0.22 0.13 0.13
TD % 0.60 0.63 0.40 1.02 0.38 0.38
Tensile strength ASTM D638 MPa 157 134 130 100 105 118
Elongatin at break % 5.1 4.5 4.5 5.0 4.0 4.1
Flexural strength ASTM D790 MPa 158 145 140 120 133 138
Flexural modulus GPa 11.8 12.1 12.5 9.4 12.6 13.0
Izod impact strength ASTM D256 J/m 251 343 270 350 200 264
DTUL (1.82MPa) ASTM D648 deg C 269 270 270 240 266 269
Soldering resistance Sumitomo
Chemical
Method
deg C 300 295 280 290 280 300

Warpage Characteristics of Each Grade

  • Method of Measuring the Level of Warpage of Long Connector
    The level of warpage of long connectors was measured using the type of tool shown in Figure 3 Figure 4 depicts the results of these measurements.
Figure 3 :
Method of Measuring the Level of Warpage of Long Connector
Figure 3 : Method of Measuring the Level of Warpage of Long Connector

Figure 4 : Level of Warpage of Long Connector

Figure 4 : Level of Warpage of Long Connector
  • Method of Measuring the Level of Warpage of Disc
    The level of warpage of disc was measured using the type of tool shown in Figure 5 and Figure 6 depicts the results of these measurements.

Figure 5 : Method of Measuring the Level of Warpage of Disc

Figure 5 : Method of Measuring the Level of Warpage of Disc

Figure 6 : Level of Warpage of Disc

Figure 6 : Level of Warpage of Disc
  • Levels of Warpage of Long Connector Before and After IR Re-flow Process
    The temperature profile for IR re-flow process is shown in Figure 7.
    Figure 8 depict the level of warpage of long connector, before and after IR re-flow process.

Figure 7 : Temperature Profile of IR Re-flow Process

Figure 7 : Temperature Profile of IR Re-flow Process
Figure 8 :
Levels of Warpage of Long Connectors Before and After IR Re-flow Process
Figure 8 : Levels of Warpage of Long Connectors Before and After IR Re-flow Process

Molding Conditions

Table 3 shows the standard molding conditions.

Table 3 : Standard Molding Conditions

  E6000HF Series, SZ6000HF
Drying conditions Approximately 130 deg C×4~24 hours
Cylinder temperature (deg C) Rear 280~320
Center 320~340
Front 340~360
Nozzle 340~360
Proper resin temperature (deg C) 350
Tool temperature (deg C) 40~120
Injection speed Medium - high speed
Injection pressure (MPa) 80~140
Maintained pressure (MPa) 20~40
Screw back pressure (MPa) 1~5
Screw rotation speed (rpm) 50~100
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