UL认证问题-请进

wx035 · 发表于 2011-1-25 15:02

广东安规检测
有限公司提供：

各位大侠，请指教。如附件图片所示的结构，其是否被视为发热件外壳。如被视为发热件外壳，其防火等级要求如何，在不更改现有塑胶件的情况下，有何改进措施？该产品欲做UL认证。

394846972 · 发表于 2011-1-25 15:30

外壳等级为V-1以上

aiduoxi · 发表于 2011-1-25 15:38

LZ的图片看起来盖顶有层铜铂，这样的话燃烧应该是V-0级的

山炮 · 发表于 2011-1-25 20:19

温控和热保护应分开放在不同极上，UL不用接地的吗？内部布线也没有适当的固定，还真的担心故障试验时漏水。（不太懂UL，随便说说）

apple2010 · 发表于 2011-1-25 22:00

做ＵＬ如果是不熟悉标准的，会做得比较痛苦，若订单很赶建议好好想一想要怎样做

Liu · 发表于 2011-1-25 23:49

UL标准的塑胶外壳防火等级不能简单地去说用什么材料，电器产品的塑胶料往往都会参考到UL746C这个标准，希望大家能够去看，同时与产品标准是最息息相关的。

这个产品看起来是一个锅类器具，估计具体应该参考UL1083。
如果适用标准是UL1083，大家可以看看一下条款，估计看完后应该知道该怎样选择了：
7.4 Among the factors that shall be taken into consideration when an enclosure is being judged for acceptability are its:
a) Physical strength;
b) Resistance to impact;
c) Moisture-absorptive properties;
d) Combustibility;
e) Resistance to corrosion; and
f) Resistance to distortion at temperatures to which the enclosure may be subjected under conditions of normal or abnormal use.
For a nonmetallic enclosure, see the enclosure requirements in the Standard for Polymeric Materials –Use in Electrical Equipment Evaluations, UL 746C. A metal enclosure or enclosure part shall be tested in accordance wiith the Metal Enclosure Impact Test, Section 36, for resistance to impact.
Exception No. 1: When considering the abnormal and severe conditions tests of UL 746C, the appliance enclosure is to be judged under the abnormal operations tests of Abnormal Operation Test, Section 46.
Exception No. 2: Thermoset materials need not be subjected to the relative thermal capability requirements of UL 746C. For a thermoset material operating at a temperature above its temperature rating, the 1000 hour aging test as specified in 43.1 shall be conducted.
7.5 A thermoplastic enclosure of an appliance provided with overheating protection (Overheating Protection, Section 22) need not comply with the flammability requirements of UL 746C if a material rated HB, and possessing 60 arcs minimum resistance to high current arc ignition, and 7 second minimum resistance to hot wire ignition is employed and all enclosure parts including ribs, grills, and the like are spaced a minimum 1/2 inch (12.7 mm) from uninsulated live parts.

如果标准不是UL1083，那估计是UL1026，但是具体要求，其实也是一样的上面这段话。大家看到其实HB的料也可以使用，关键是后面带了个尾巴，这个尾巴很关键，留下话题，大家讨论尾巴，其实这个尾巴就是安规工程师是否真正入行的表现

tianchi0305 · 发表于 2011-1-29 07:31

也要看具体的吧

一地落叶 · 发表于 2011-1-29 08:12

建议买个电饭锅来参考一下，你那塑料件上面没有散热孔，我估计那样温升会很快，会导致通不过，还有塑料必须是VO级的了，虽然我没做过类似产品，但我们线盘，插座上面对这要求是非常严格的，UL认证产品的附材应该要有UL证书，我想那个塑料要有UL黄卡的

gaoyimin123 · 发表于 2011-1-29 08:38

这是个什么产品?用UL什么标准?先提供支撑带电体的材料要求,外壳的要求是对应标准内有说明,挺多的外壳用HB也是可以的,但是要附加很多的测试,生产商为了省去测试,一般不用HB的材料.

gaoyimin123 · 发表于 2011-1-29 08:41

Suitability for thermoplastic materials to be in direct support of live parts, below are the suitable properties for each flammability, Per UL 746C, Table 8.1
可以用来直接支撑带电体的塑料其HAI/HWI/CTI的指数需符合下表。
V-0 V-1 V-2 HB
HAI 3 2 2 1
HWI 4 3 2 2
CTI 4 4 4 4

Suitability for thermoplastic materials to be in direct support of live parts, below are the suitable properties for each flammability, Per UL 746C, Table 8.1
可以用来直接支撑带电体的塑料料其HAI/HWI/CTI的指数需符合下表。

V-0 V-1 V-2 HB
HAI 3 2 2 1
HWI 4 3 2 2
CTI 4 4 4 4
数字越小，代表HAI/HWI/CTI的性质越好。
例如：奇美PA-766 UL黄卡摘录
                                 H D
      Min.       H H R T I V 4 C
      Thk Flame W A Elec Mech T 9 T
Material Dsg Color mm Class I I       Imp Str R 5 I
PA-766 ALL 1.5 V-0 1 0 60 60 60 0 7 2
      2.5 5VA - - 60 60 60
      3.0 5VA 0 0 60 60 60
在最小厚度大于1.5mm时，其耐燃等级是UL 94V-0， HWI=1、HAI=0、CTI=2，因此看回上表HWI<4、HAI<3、CTI<4，符合上表，所以PA-766在最小厚度大于1.5mm时可以直接支撑带电体。
但若黄卡中HAI、HWI值为 “-“，则代表厂商申请此料时未做相关测试，所以是不能认可为可直接接触带电体的。
Hot-Wire Ignition (HWI; ASTM D3874, IEC 60695-2-20 ) — Performance is expressed as the mean number of seconds needed to either ignite standard specimens or to burn through the specimens without ignition.
HWI Range
Mean Ignition Time (in sec) Assigned
PLC
120 and longer 0
60 through 119 1
30 through 59 2
15 through 29 3
7 through 14 4
Less than 7 5
High Current Arc Ignition (HAI; ANSI/UL 746A ) — Performance is expressed as the number of arc rupture exposures (standardized as to electrode type and shape and electric circuit) that are necessary to ignite a material when they are applied at a standard rate on the surface of the material.
HAI Range
Mean Number of Arcs
to Cause Ignition Assigned
PLC
120 and greater 0
60 through 119 1
30 through 59 2
15 through 29 3
Less than 15 4
Comparative Tracking Index (CTI; ASTM D3638 ) — Expressed as that voltage which causes tracking after 50 drops of 0.1 percent ammonium chloride solution have fallen on the material. The results of testing the nominal 3 mm thickness are considered representative of the material's performance in any thickness.
CTI Range
Tracking Index
(in volts)
Assigned
PLC
600 and greater 0
400 through 599 1
250 through 399 2
175 through 249 3
100 through 174 4
Less than 100 5

黄卡的说明COLUMN HEADING ABBREVIATIONS
The following abbreviations may be used in the column headings in the individual Recognitions:
Abbreviation Term
Flame Class ANSI/UL 94 Flammability Classification
Material Dsg Material Designation
Col Color
Min Thk Minimum Thickness
Thk Rg Thickness Range
Den Range g/cc Density Range, g/cc
Elec Electrical
RP Radiant Panel
RTI Relative Temperature Index
HWI Hot-Wire Ignition
HAI High Current Arc Ignition
HVTR High Voltage Arc Tracking Rate
D495 Arc Resistance
CTI Comparative Tracking Index
Mech Mechanical
Tnsl Tensile
Elong Elongation
Str Strength
Imp Impact

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