RoHS stands for Reduction of Hazardous Substances

The list of chemicals on which this regulation works are as follows:

• Lead (Pb)

• Mercury (Hg)

• Cadmium (Cd)

• Hexavalent Chromium (Cr6+)

• Polybrominated Biphenyls (PBB)

• Polybrominated Diphenyl Ethers (PBDE)

• Bis(2-Ethylhexyl)phthalate (DEHP)

• Benzyl butyl phthalate (BBP)

• Dibutyl phthalate (DBP)

• Diisobutyl phthalate (DIBP)

All follow the limitation of a maximum of 0.1%

The directive has been taken to be much more than only Lead Directive as for some electronic industries the product without Lead stays to be RoHS Complaint in nature. However, not all chemicals in the list are RoHS Complaint in nature.

LDR or Light Dependent Resistor that we often use in our projects is one of those simple components that are not RoHS compliant. As we all know, the functionality of LDR to be triggering certain function on detection of light, it uses Cadmium Sulphide(CdS) in it. Cadmium Sulphide although falls in the RoHS list but is excepted due to some military or medical grounds and thus has been introduced in the commercial products.

These sets of rules greatly affect the manufacturing companies of electronic goods as these rules have direct connections to customer rights and market values. When an electronic manufacturing company starts, it first meets the need of the market and manufactures a product according to it. It then selects a small target market and maps the success and demand rate of the product. Now as it aims for the bigger market, the legislation intervenes and these rules come to be addressed to. These products are generally small electronic components that are used in other bigger electronic systems.

Thus, the main problem arrives for the companies, when the product such as LDR does not have any such immediate alternative that can be manufactured. The work becomes all the more difficult for the one designing the electronic system using the following component as they now have to design a full circuit satisfying the Ross rules to validate that particular functionality.

For example, in place of LDR, the photodiode can be used as reverse biased along with a resistor. Even after this method, the alternate circuit made in place of the product often turns out to be not as effective as the product itself. It also hampers the manufacturing process, as well as more time and work, is invested in that. 

After the Ross complaint filter is passed, the product goes through another set of filtering before getting launched in the market. This set of filtering rules is termed to be as REACH which stands for Registration Evaluation Authorization and restriction of Chemicals. REACH has a list of around 200 chemicals that it restricts from being used in the product. This rule is strictly issued on companies that transact over 1 tonne of chemicals per year for their work. This list of chemicals is termed as SVHC that is, Substance of Very High Concern.

The stage of distributors strictly follows the rule of REACH and thus even after passing the Ross restrictions, the product may get stopped by these sets of rules. These sets of chemicals are a concern that needs to look after as even if these chemicals do not seem to be harmful on the first go, but are seen to be turning toxic and harmful under recycling. Thus, the rules of REACH are the ones that need to be followed as well.

Electronic systems formed concerning the food industry strictly need to follow these rules as they are the ones that are directly connected to the health concerns of the customers and as well do not have proper medical supervision in the industry. 

Proper documentation is provided once the product or component satisfies all these requirements and thus it officially becomes usable for commercial purposes. This documentation or certification is important, as they can be asked for in any level of survey and even by the customer. The company in that case always stays liable to provide the certification under public interest.

The testing of chemicals while manufacturing the product is also an important measure that needs to be followed. Companies guiding in this matter of testing procedures are already present and one can consult them for the need.

It is better to be always dealing with the rules. Saving a few amounts of money while initializing the manufacturing house by avoiding these rules can cost the whole product after getting launched in the market. Being cheap is not always helpful for the production process in the long run.