JB/T 8539-1997Plastics extrusion blow moulding machines (English PDF)

5.1.8

The molding machines shall operate stably and reliably during normal operation; the control system shall be highly responsive, with clear and accurate indication.

5.1.9

For the molding machines equipped with the multi-point parison wall thickness control device, the repeated positioning accuracy of die opening amount shall be less than 0.1 mm.

5.2 Parison requirements

5.2.1

The parison shall be smooth, well plasticized.

5.2.2

For the molding machines equipped with a storage head (hereinafter referred to as the storage type molding machines), at any set value, the quality uniformity of injection parison shall not be greater than 3%.

5.2.3

For continuous extrusion molding machines (hereinafter referred to as continuous molding machines), within the same time interval, the quality uniformity of extrusion parison shall not be greater than 5%.

5.3 Safety protection

5.3.1

If the operating conditions of the components, instruments and accessories of the molding machines, 2 m above the ground, need to be observed, it needs to provide skidproof foot rests, platforms or ladders as well as reliable fence and handrail, as specified in GB 17888.3.

5.3.2

Safety protective devices shall be provided around the molding machines on which molds are installed. If safety doors are installed as protective devices, they shall be fixed reliably without opening itself. If photoelectric protective devices are used, it shall be ensured that they operate reliably and are provided with visible warning signs. The mold clamping part shall be provided with a reliable safety interlocking system. In normal operating conditions, the safety doors shall not be closed or block the photoelectric device; the mold clamping part shall not be closed.

5.3.3

The storage type molding machines shall give alarms when the storage amount achieves the limit value and the extruding machines shall stop operating.

5.3.4

The molding machines shall have emergency stop buttons and rapid mold opening buttons. Press the emergency stop button and then the extruding machines and oil pumps stop operating; and then the other actions stop. Press the rapid mold opening button, and then the template immediately opens.

5.3.5

The molding machines shall be free from any abnormal scream or impact sound. The accompanied by a quality certificate. Before the delivery of each molding machine, the continuous idle operation test for not less than 4 h shall be carried out (with the extruding device and head in idle); check the specifications in 5.1.5, 5.1.6, 5.3.1 and 5.4 before the test; and during the test, check the specifications of 5.1.2 ~ 5.1.4, 5.1.7,

5.1.8, 5.1.9 and 5.3.2 ~ 5.3.4.

7.2 Type test

During the type test, carry out sampling inspection. Take 1 sample each time. If one of the test items is a fail, then take another sample; if there is still any non-conformance item, then the type test is a fail. The continuous load test for not less than 8 h shall be carried out in the type test; during the test, check the specifications of 5.2.1 ~ 5.2.3 and 5.3.5.

In one of the following circumstances, the type test shall generally be carried out.

-- during the trial-production pattern evaluation of a new product or an old product whose production is transferred to another location;

-- in case of any significant change in structure, process or material after mass production, which may influence the product properties;

-- at least 1 sample taken each year during normal production;

-- when the production is resumed after a long term of production halt;

-- when there is any significant difference between the results of an exit-factory inspection and those of the last type test;

-- when a national quality supervision institution requires so;

8.1 Marking

A product plate shall be fixed for each product at an appropriate, visible location. The types, dimensions and technical requirements of the plate shall be as specified in GB/T 13306. The product plate shall include the following content.

a) product name and type;

b) major technical parameters of product;

c) manufacturer name and trademark;

GB/T 25156-2020 | GB 20055-2006 | JB/T 6490-2015 |

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