MH-25560718 UL电线表面印字耐磨试验装置|印字耐磨块|Durability of ink printing
符合UL2556 第7.18节 Durability of ink printing标准，用于检测电线护套印刷字体的耐磨性能。
荷重尺寸: 25×50mm(1×2 inch)
UL 25567.18 Durability of ink printing
This test establishes the method for determining the durability of ink printing.
The apparatus shall consist of
a) a forced-circulation air oven in accordance with Clause 4.2.3, Item (i);
b) a temperature-measuring device with an accuracy of ±1 °C;
c) a kraft felt with a thickness of 1.2 ±0.25 mm (0.05 ±0.01 in) not having more than 30% wool content and the remainder of the composition being rayon; and
d) a weight block with a machined face of 25 mm (1in) by 50 mm (2 in) and a uniform height to ensure even weight distribution throughout the area of the lower face. Clamps or other means shall be provided for securing the craft felt in place. Without the felt in place, the weight block and clamps shall be 450 ±5g(1 ±0.01 lb).
7.18.3 Preparation of specimen
Two specimens shall be taken from ﬁnished wire or cable, or from the wire or cable during manufacture.
The specimens shall be 300 mm (12 in) in length with the printing centered. The specimens shall be handled minimally and shall not be wiped, scraped, or otherwise cleaned in any way.
126.96.36.199 One specimen shall be conditioned in a forced-circulation air oven at the speciﬁed temperature and for the speciﬁed period of time. The other specimen shall be maintained at ROOM TEMPERATURE for a minimum of 24 h.
188.8.131.52 Upon removal from the oven, the conditioned specimen shall be allowed to rest for a minimum of 60 min prior to testing. Following the rest period, the specimen shall be placed and secured on a solid, ﬂat, horizontal surface with the printing up and at the center of the length of the specimen.
184.108.40.206 With the specimen secured in place, the felted surface of the weight block shall be placed horizontally on the printed area of the specimen with the 50 mm (2in) dimension of the felted surface parallel to the length of the specimen. With the weight block resting freely on the specimen, the weight block shall be slid lengthwise by hand along the printed area of the specimen for a total of three cycles, each cycle consisting of one complete back-and-forth motion covering the center 250 mm (10 in) of the
specimen. Three cycles shall be completed at an even pace within a total of 5 to 10 s.
220.127.116.11 The procedure described in Clause 18.104.22.168 shall be repeated on the remaining specimen.
22.214.171.124 The felt may be used for several tests, but shall be replaced as soon as the ﬁber is ﬂattened or becomes soiled. When not in use, the weight shall not be stored resting on the felt surface.
7.18.5 Results and calculations
The legibility of both specimens shall be examined with NORMAL VISION and noted.
The report shall include, as a minimum, indication of legibility of ink printing, temperature, and duration of conditioning.