ASTM D3123-1998(2004) Standard Test Method for Spiral Flow of Low-Pressure Thermosetting Molding Compounds《低压热固性模塑料螺旋形流动的试验方法》.pdf

1、Designation: D 3123 98 (Reapproved 2004)Standard Test Method forSpiral Flow of Low-Pressure Thermosetting MoldingCompounds1This standard is issued under the fixed designation D 3123; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,

2、the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers a procedure for measuring thespiral flow of thermosetting molding compounds (sof

3、t or verysoft) designed for molding pressures under 6.9 MPa 1000 psi.It is especially suited for those compounds that may be used forencapsulation or other low pressure molding techniques.Textile-reinforced compounds should not be tested using thistest method. It involves the use of a standard spira

4、l flow moldin a transfer molding press under specified conditions ofapplied temperature and pressure with a controlled chargemass.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establis

5、h appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 1There is no equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:2D 883 Terminology Relating to PlasticsD 958 Practice for Determining Temperatures of StandardASTM Mo

6、lds for Test Specimens of PlasticsE 105 Practice for Probability Sampling of Materials3. Terminology3.1 Definitions Definitions in this test method are consis-tent with Terminology D 883.4. Significance and Use4.1 The spiral flow of a thermosetting molding compound isa measure of the combined charac

7、teristics of fusion underpressure, melt viscosity, and gelation rate under specificconditions.4.2 This test method is useful as a quality control test and asan acceptance criterion.4.3 This test method, by itself, is not a valid means forcomparing the moldability of similar or different moldingcompo

8、unds because it cannot duplicate actual conditionsprevalent in different types of production molds.4.4 This test method is presently intended for use at atransfer pressure of 6.9 MPa 1000 psi and a mold temperatureof 423 6 3 K (150 6 3C 302 6 5F).5. Apparatus5.1 Transfer Molding Press with a minimum

9、 150 by150-mm 6 by 6-in. platen area, transfer piston pressurepotentially greater than 6.9 MPa 1000 psi, sufficient clamppressure to prevent flashing, and a minimum plunger speed of25.4 mm 1 in./s without load. The plunger should beequipped with at least one peripheral sealing groove. It isrecommend

10、ed that a pot diameter between 31.75 and 44.45 mm1.25 and 1.75 in. be used whenever a choice is possible.NOTE 2Preliminary evidence indicates that, in many cases, reason-able correlations may be achieved between laboratories using presses withdifferent pot diameters. Typical examples are presses wit

11、h pot diameters of31.750, 38.100, and 44.450 mm 1.250, 1.500, and 1.750 in. However, afew well-documented cases are recorded where differences in pot diam-eters, even within this listed range, have caused large differences inflow-length readings. Therefore, for best interlaboratory correlation it is

12、recommended that identical pot diameters be used.5.2 Standard Spiral-Flow Mold shown in Fig. 1 shall beutilized.6. Materials6.1 Molding Compound:6.1.1 Any thermosetting molding compound with a spiralflow between 762 and 1270 mm 30 and 50 in. as determinedat the standard temperature and pressure of t

13、his test can beevaluated.NOTE 3Since the only commercially available molds are calibrated ininches, spiral-flow length will be reported in these units. Conversion to SIunits can readily be made by multiplying the flow length, in inches, by theappropriate conversion factor, 25.4 mm/in.NOTE 4There is

14、considerable evidence that the test is usable over awider range of flow lengths, but this has not yet been confirmed byinterlaboratory testing.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.30 on Thermal Properties(Se

15、ction D20.30.08).Current edition approved October 1, 2004. Published December 2004. Originallyapproved in 1972. Last previous edition approved in 1999 as D 3123 - 98(99)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For An

16、nual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.1.2 Fo

17、rmThe form of the molding compound shall beloose powder or granules at 296 6 2 K (23 6 2C 73.4 63.6F).NOTE 5Preforms or pellets may be used if found necessary; however,flow length may be affected by their use.7. Sampling7.1 Unless otherwise agreed upon between the seller andpurchaser, sampling shall

18、 be in accordance with PracticeE 105. Sampling, based on engineering principles, prior topackaging shall be considered an acceptable alternative.8. Conditioning8.1 ConditioningAll molding compounds shall be testedin “as-received” condition. For referee testing, all materialshall be shipped and store

19、d in moisture-barrier containers.They shall be stored for a minimum of 24 h at the standardlaboratory temperature, before breaking the seal on the con-tainer. Care should be taken to preserve the “as-received”moisture content and tests shall be made as soon as possibleonce the container has been ope

20、ned. Alternative methods ofconditioning samples may be used, provided they are mutuallyagreed between manufacturer and purchaser.9. Test Conditions9.1 Spiral-Flow MoldThe mold shall be clean and freefrom any mold-release agents or lubricants. Several prelimi-nary moldings shall be made with the mate

21、rial to be tested topurge the helical runner before beginning the test. Thisprocedure is essential when changing from one compound toanother and is recommended as a routine practice.9.2 Molding Conditions:9.2.1 TemperatureA temperature of 423 6 3 K (150 63C 302 6 5F) shall be maintained on the mold

22、and transferplunger. The temperature may be measured in accordance withthe procedures described in Practice D 958 or by thermo-couples attached to the mold and plunger. The temperatureshould be allowed to reach equilibrium by waiting at least 3min between moldings.9.2.2 Transfer PressureThe actual p

23、ressure applied to thecompound at the base of the pot shall be 6.90 6 0.17 MPa1000 6 25 psi. In most presses the gage pressure is notsufficiently accurate for determining transfer pressure. There-fore, the force exerted by the plunger shall be measured bysome means such as an accurately calibrated d

24、irect-readingforce gage or proving ring. The actual transfer pressure is thencalculated as pascals or pounds per square inch by dividingthe force in newtons or pounds-force by the plunger area insquare metres or square inches.9.2.3 Charge MassThe mass of the compound shall bedetermined empirically s

25、o that the thickness of the molded cull(cured compound on top of the sprue plate of the mold), aftertest, is between 3 and 3.5 mm 0.12 and 0.14 in. TheFIG. 1 Standard Spiral-Flow MoldD 3123 98 (2004)2relationship between the amount of compound and the dimen-sions of the transfer pot is critical in o

26、btaining meaningful,reproducible spiral-flow values. The use of excessive amountsof compound will result in shorter, inconsistent spiral flows.For transfer pots 31.75 to 44.45 mm 1.25 to 1.75 in. indiameter, 20 g of compound is suggested as the starting chargemass.9.2.4 Transfer Plunger SpeedThe tra

27、nsfer plunger speedwithout load (as described in 5.1) shall be controlled between25 and 100 mm/s 1 and 4 in./s. The elapsed time betweeninsertion of the charge into the pot and the development ofpressure on the charge by the plunger shall be no more than 5seconds. Too long a dwell time before transf

28、erring will causeerratic results.9.2.5 Press Cure TimeSufficient cure time shall be used tofacilitate easy removal of the spiral from the mold. This timewill vary with the compound under test. Manufacturersrecommendations for cure should be followed.9.2.6 Transfer Plunger GroovesIf the transfer plun

29、ger isequipped with grooves, they must be cleaned before each newmolding.9.3 Flow LengthFlow length shall be the farthest point atwhich the material completely fills the cross section of thehelix runner.10. Procedure10.1 Heat the mold and transfer the plunger to 423 6 3K(150 6 3C 302 6 5F).10.2 The

30、plunger preferably is equipped with sealinggrooves. These must be cleaned free of compound beforechecking pressure and before each molding.10.3 Using a force gage or proving ring, adjust the transferpressure to 6.90 6 0.17 MPa 1000 6 25 psi.10.4 Weigh out the compound to the nearest 0.1 g asprevious

31、ly determined to yielda3to3.5-mm 0.12 to 0.14-in.molded cull.10.5 Place the compound in the transfer pot and activate thetransfer cycle immediately. Cure the compound as recom-mended for easy removal.10.6 Open mold and remove the cured material. Read thespiral flow length directly from the molded sp

32、ecimen at thepoint of farthest continuous flow to the nearest 0.25 in. (Note3).10.7 Repeat 10.4 to 10.6 until three consecutive flowreadings agree to within 65 % of their average.11. Report11.1 Report the following information:11.1.1 The accurate identity of the sample tested,11.1.2 Average spiral-f

33、low length reported to the nearest6.35 mm 0.25 in.,11.1.3 The temperature and pressure used for the test,11.1.4 The form of the material (granulated, preformed,etc.),11.1.5 The average cull thickness and charge mass used, and11.1.6 The ram diameter and speed.12. Precision and Bias12.1 Statistical an

34、alysis of round-robin data3indicates thatwithin a given laboratory the averages of three flow lengthdeterminations on a typical material will not differ from eachother by more than 1.29 in. at a 95 % confidence level. Anaccurate estimate of the reproducibility between laboratories iscurrently unavai

35、lable.13. Keywords13.1 spiral flow; thermosetsSUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue,D 3123 - 98(99)e1, that may impact the use of this standard. (October 1, 2004)(1) Five year review. Reapproval without change.ASTM Inter

36、national takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely

37、their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand shou

38、ld be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Stan

39、dards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).3Round-robin data for this test method are available from ASTM Headquarters.Request RR: D20-1028.D 3123 98 (2004)3