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GB/T 25156-2020 English PDF (GBT25156-2020)

GB/T 25156-2020 English PDF (GBT25156-2020)

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GB/T 25156-2020: General specifications and inspection methods of rubber and plastics injection moulding machines
GB/T 25156-2020
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.120; 83.200
G 95
Replacing GB/T 25156-2010, GB/T 25157-2010
General specifications and inspection methods of rubber and
plastics injection moulding machines
ISSUED ON: MARCH 31, 2020
IMPLEMENTED ON: FEBRUARY 01, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Normative references ... 5 
3 Terms and definitions... 6 
4 Models and basic parameters ... 6 
5 Requirements ... 7 
6 Testing methods ... 9 
7 Inspection rules ... 29 
8 Marking, packaging, transportation, storage ... 30 
Appendix A (Informative) Model ... 32 
Appendix B (Normative) Basic parameters ... 33 
References ... 35 
General specifications and inspection methods of rubber and
plastics injection moulding machines
1 Scope
This standard specifies the model and basic parameters, requirements, testing methods,
inspection rules and signs, packaging, transportation, storage of rubber and plastic
injection molding machines.
This standard applies to single-screw plunger, single-station, vertical/horizontal rubber
injection molding machines AND single-screw, single-station, horizontal plastic
injection molding machines (hereinafter referred to as injection molding machines).
2 Normative references
The following documents are essential for the application of this document. For dated
references, only the dated version applies to this document. For undated references, the
latest edition (including all amendments) applies to this document.
GB/T 191 Packaging - Pictorial marking for handling of goods
GB/T 321-2005 Preferred numbers - Series of preferred numbers
GB/T 3682.1 Plastics - Determination of the melt mass-flow rate (MFR) and melt
volume-flow rate (MVR) of thermoplastics - Part 1: Standard method
GB/T 3785.1-2010 Electroacoustics - Sound level meters - Part 1: Specifications
GB/T 6388 Transport package shipping mark
GB/T 13306 Plates
GB/T 13384 General specifications for packing of mechanical and electrical product
GB 22530 Safety requirements of injection moulding machines for rubber and
plastics
GB/T 36587 Rubber and plastics machinery - Terminology
HG/T 3120 The general technological requirements for the appearance of the rubber
and plastic machinery
HG/T 3228-2001 General specifications of painting for rubber and plastics
machinery
3 Terms and definitions
The terms and definitions, which are defined in GB/T 36587, as well as the following
terms and definitions, apply to this document. For ease of use, some terms and
definitions of GB/T 36587 are repeated below.
3.1
Repeatability of mold opening position
After the mold opening action under the same conditions, the consistency of the
actual position of the moving platen, when the mold opening is terminated.
3.2
Repeatability of injection position
The consistency of the actual position of the screw or plunger, at the end of the
injection, after the injection action under the same conditions.
3.3
Dry cycle time
Dry cycle
Without injection and pre-molding action, the time required for the clamping
mechanism to run for one cycle, which includes mold closing time, mold opening
time, conversion time.
[GB/T 36587-2018, definition 3.5.52]
4 Models and basic parameters
4.1 Model
See Appendix A for the model of the injection molding machine.
4.2 Basic parameters
See Appendix B for the basic parameters of the injection molding machine.
working surface of the hot plate shall meet the following requirements:
a) For electric heating (the size of the hot plate is not more than 1000 mm x 1000
mm), steam heating, oil heating, the temperature difference shall be controlled
within 6 °C;
b) For electric heating (the size of the hot plate is larger than 1000 mm x 1000 mm),
the temperature difference shall be controlled within 10 °C.
5.4 Safety requirements
Safety requirements shall comply with the provisions of GB 22530.
6 Testing methods
6.1 General testing methods
6.1.1 Testing of operation control mode
Check whether the manual operation control mode, semi-automatic operation control
mode, automatic operation control mode are available and effective.
6.1.2 Motion detection of moving parts
Set the oil pressure of the system to 25% of its rated value. Perform each of mold
opening and closing, hydraulic ejection and retraction, injection nozzle advance and
retraction, for three times, to check whether the moving parts are crawling, jamming,
or having obvious shock.
6.1.3 Detection of the coaxiality between the center of the injection nozzle hole and
the positioning hole of the template mold
Move the injection nozzle head to the measurable position of the positioning hole of
the fixed platen mold. Use a vernier caliper, to measure the values of the four positions
(A, B, C, D) in Figure 1. Take the difference, between the maximum value and the
minimum value, as the coaxiality tolerance.
Then carry out empty injection. After the material is cooled, use the standard weighing
instrument to weigh out its mass W plasticizing (g). Then calculates the plasticizing
capacity G (g/s), G = W plasticizing/2T plasticizing. This testing is carried out as such for three
times. Finally, take the arithmetic mean of the three calculation results, as the
plasticizing ability value.
6.1.11 Testing of injection rate
6.1.11.1 Testing conditions
The testing conditions of injection rate shall be as specified in a) ~ f) of 6.1.10.1.
6.1.11.2 Testing method
Carry out the empty injection. Use a stopwatch or other more accurate timing device,
to record the injection time t injection (s). After the material is cooled, use a standard
weighing instrument, to weigh its mass W injection (g). Then calculate the injection rate q
(g/ s), q = W injection/t injection. This testing is performed as such for three times. Take the
arithmetic mean of the three calculation results, as the injection rate value.
6.1.12 Testing of actual injection volume
6.1.12.1 Testing conditions
The testing conditions for actual injection volume are as specified in a) ~ f) of 6.1.10.1.
6.1.12.2 Testing method
Carry out the empty injection. After the material is cooled, use a standard weighing
instrument, to weigh its mass. Carry out testing for three times. Finally take the
arithmetic mean of the three test results, as the actual injection volume value.
6.1.13 Testing of injection pressure
6.1.13.1 Testing method 1
Set the injection molding machine to the semi-automatic operation mode, without
material. Run the injection to the end. Determine the system's working pressure p0,
according to the pressure gauge. Then calculate the injection pressure p, according to
formula (5).
Where:
p - The injection pressure, in megapascals (MPa);
A0 - The effective cross-sectional area of the injection piston, in square centimeters
(cm2);
p0 - The working pressure of the system, in megapascals (MPa);
AS - The cross-sectional area of the screw or barrel plunger, in square centimeters
(cm2);
n - The number of injection cylinders.
6.1.13.2 Testing method 2
The test raw material is recommended to use polystyrene (PS); the heating temperature
is 216 °C ± 6 °C. Install a pressure detection device, which has an accuracy of 0.01
MPa, at the nozzle. After the machine enters a stable state, se...
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