This standard specifies the test method for the shrinkage of thermoplastics during injection molding. This standard is applicable to thermoplastics. GB/T 15585-1995 Determination of shrinkage of thermoplastics during injection molding GB/T15585-1995 Standard download decompression password: www.bzxz.net

UC 678. 4, 073 - 678 1 017 - 223G31
National Standard of the People's Republic of China
GB/T 15585—1995
Determination of shrinkage foninjection noulding thermoplaslics1995-06-12Promulgated
State Administration of Technical Supervision
Implementation on 1995-12-01
National Standard of the People's Republic of China
Determination of shrinkage foninjection noulding thermoplaslicsSubject Content and Applicable Scope
This standard specifies the test method for the shrinkage of injection moulding of thermoplastic materials. This standard applies to dry thermoplastics.
2 Reference standards
GB2035--8 Plastics Specifications and Definitions
GA2918-82 Plastics Test Specimen Conditions and Test Environments 3 Terminology
3-1 Injection Molding mauldingGB/T155B5-1995
A method in which thermoplastic or thermosetting molding materials are first plasticized in a heated material tube, and then pushed into the mold cavity of a fitting by a cylindrical moving screw.
32 Molding shrinkage ratio mouldingshrinkag The ratio of the mold size to the cavity size of the common mold should be expressed as a percentage. 4 Equipment and equipment
4.1 Injection molding machine
The selected injection molding machine should meet the melting and mixing specifications required by the material, operate within the range of 1/2 to 34 of its specified injection plate, and be able to fill the sample mold with a screw that is not commercially available to meet the requirements of the type of thermoplastic molding materials. 4.2 Test injection mold
Measure the shrinkage parallel to the material channel. The size of the mold used is 12.? mm×127mm×3.2mm, the average opening size is 6.4mm wide and 3.2mm deep.
The cavity diameter of the tester used to measure the shrinkage rate in the diameter direction is 102mm, the length is 3.2mm, and there is a diameter side opening, the opening is 12.7mm+depth 3.2mm.www.bzxz.net
4.3 Measuring tools
Measuring tools that can measure the size of the sample and the corresponding mold can be used, with an accuracy of mm. 5 Samples
5.1 Size
5.1.1 For measuring the shrinkage rate in the direction parallel to the material, a pictographic sample with a size of 12.7mm×127mm×3.2mm is used, and its opening is set at the end.
National quality control technology and quantity adjustment week 1995-06-72 batch pool 1995-12-01 sales support
GR/T155B5-1995
5.1.2 For the test sample of the upward diameter collection rate, the national film sample with a diameter of 102mm and a thickness of 3.2mm is adopted, which is the longitudinal flow port,
5 samples in each group:
6 Test steps
6.17 Measure the cavity size
After the mold is aged for 211 days at 23+2℃, measure its cavity size with an accuracy of 0.02mm.6.2 Injection molding
The injection molding process is carried out in accordance with the relevant technical conditions of control materials. 6.3 Selection of warp groups
Before measuring the size of the sample, use a flat plate or angle gauge and a feeler gauge to check the warping deformation of the sample. If the deformation exceeds the main % of its measured size, it should be included.
6.4 Design of mold shrinkage
6.4.7 Test piece
The sample is injected into the mold, that is, stored and measured under the standard environment specified in GB2918. The storage time is 1.-2h. The shrinkage rate obtained by the two measurements is the initial shrinkage rate or -2-h\shrinkage rate: storage for 16~24h, the measured shrinkage is the \24-h\shrinkage rate; the shrinkage obtained after storage for 40~48h is the standard shrinkage rate or "48·\shrinkage rate. 6.4.2 Measurement method
6.4.2-1 Measurement of long sample
The length between the two parallel end faces of the strip test specimen is the distance between the effective marks. 6.4.2.2 Preparation of the sheet test specimen
Measure the diameter of the sample in the parallel and perpendicular flow directions. 5.4.3 Testing requirements
Measure the inner cover twice in the fixed direction of each sample with an accuracy of 0.02mm, and take the arithmetic mean. 7.1 General plastic shrinkage cost (MS) is calculated by the following formula: MS=
Formula, S—plastic shrinkage rate,
L,---mold cavity size; mm
L—sample size .mm
7.2 The test results are expressed as the average value of 5 specimens. The shrinkage rates of different sides should be expressed separately. a. Test report
The test report should include the following contents:
Name, brand, manufacturer, batch number, date, etc. of the molding material, L. Specifications of the injection molding machine, model number, manufacturer, manufacturing date and screw type used, etc. c. Detailed record of each special preparation work, such as some materials must be dried before injection molding, and the actual baking temperature and time must be recorded:
d. Actual dimensions of the mold cavity| |tt||GB/T15585—1995
.: Record of injection molding process conditions, including pre-injection temperature, mold temperature, injection molding temperature, injection size, injection pressure, holding time and mold cycle, etc. Record of test conditions, including ambient temperature and shrinkage of the mold and the actual size of the sample, and the corresponding shrinkage time of the sample.
Use the measured data to calculate the effectiveness of the model and the shrinkage limit of the model;
Regular and replacement:
1. Other matters that need to be mentioned.
Additional remarks:
This standard is equivalent to ASTMD955 <Standard Test Method for Measuring Plastic Growth Rate from Mold Size>. The technical standard is proposed and managed by the National Plastics Standardization Technical Committee Mechanical Industry Plastic Products Branch. This standard was jointly drafted by the Shanghai Materials Research Institute of the Ministry of Machinery Industry and Chengdu University of Science and Technology. The main drafting units included Jinhua Testing Machine Factory, Jinluo Petrochemical Nanjing Plastic Factory, and Nanjing Zhengyuan Automation Research Institute. The main drafters of this standard are Lan Xiaohong, Bo Liang, Wei Dong, Wu Fen, and Ling Zhengyuan.
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