RoHS, a mandatory standard set by the EU legislation, is called "Restriction of Hazardous Substances" for restricting the use of certain harmful components in electrical appliances. The standard has been implemented since July 1, 2006. It is mainly used to standardize the materials and process standards of electronic electrical products, making it more conducive to human health and environmental protection. The aim of this standard is to eliminate the six substances of lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls and polybrominated diphenyl ether in the electrical products of electrical machinery, and the concentration of lead can not exceed 0.1%.
RoHS:
Only new products to be launched on 1 July 2006.
Include household incandescent lamps and light sources.
Special instructions or regulations for safety and health requirements should not be violated - Vehicle ELV, Vehicle instructions; Battery instructions, 91/15/eec, 93/86/EEC&98/101/EC
Not included: medical equipment or monitoring equipment (WEEE instructions no. 8, 9);Maintenance spare parts for the market before July 1, 2006;Before July 1, 2006, the market will be re-used products.
Toxic substances limited:
· heavy metal:
- Lead the Lead;
- Mercury Mercury;
- Cadmium Cadmium;
Chromium (VI) hexavalent Chromium.

Certain brominated flame retardants:
Polybrominated biphenyls (PCBS), Polybrominated biphenyls (PBB) 's;
Polybrominated diphenyl ether, Polybrominated diphenyl ethers (PBDE) 's.
The maximum limit is:
· cadmium: 0.01% (100ppm);
· lead, mercury, hexavalent chromium, polybrominated biphenyls, polybrominated diphenyl ether: 0.1% (1000ppm).

Six kinds of harmful substances
RoHS for all the production process and raw materials that may contain the above six kinds of harmful substances in electrical and electronics products, mainly including: white home appliance, such as refrigerators, washing machines, microwave ovens, air conditioners, vacuum cleaners, water heaters, etc., black appliances, such as audio and video products, DVD, CD, TV receiver, IT products, digital products, communication products, etc.;Electric tools, electric electronic toys, medical electrical equipment.
1. Examples of lead (Pb) using this material: solder, glass, PVC stabilizer
2. Examples of mercury (Hg) (mercury) using the substance: thermostat, sensor, switch and relay, light bulb
3. Examples of cadmium (Cd) using the substance: switches, springs, connectors, shells and PCB, contacts, batteries
4. Example of Cr 6+ using this substance: metal with corrosion coating
5. Examples of PBB using the substance: flame retardant, PCB, connector, plastic shell
6. Examples of PBDE using the substance: flame retardant, PCB, connector, plastic shell

The test principles
According to the eu WEEE&RoHS directive, the broadcast metrology test (GRGT) is to split the product according to the material, and carry out the detection of harmful substances with different materials.Generally speaking:
· metal materials should be tested for four harmful metal elements such as Cd/Pb/Hg mercury/Cr6 + hexavalent chromium
· in addition to checking these four harmful heavy metal elements, plastic materials should also be tested for the detection of brominated flame retardants (PBB/polybrominated polybromide PBDE).
· the packaging materials for different materials also need to be tested separately for heavy metals in packaging materials (94/62 / EEC).
The following is the upper limit concentration of six harmful substances in RoHS:
Cadmium: less than 100 PPM
Lead: less than 1000ppm
The steel alloy is less than 3500ppm
Aluminum alloy is less than 4000ppm
The copper alloy is less than 40000ppm
Mercury: less than 1000 PPM
Hexavalent chromium: less than 1000ppm