What is Electronics Manufacturing Service (EMS) company?

What are the job functions within an EMS?

An electronic manufacturing service (frequently abbreviated EMS) company is a company that manufacturers and assembles electronic assemblies for other companies.

Like other companies, an EMS is composed of departments.  Many departments within an EMS – such as Accounting, Sales, and Customer Service – also exist in non-EMS companies.  But it is common for an EMS to have specialized departments such as Design Engineering and Test Engineering.  The following is a list of departments that are typically found within an EMS, along with a description of their job function.

Typical Departments within an EMS

The Sales department is usually the first department that interacts with a prospective customer.  One or more members from the Sales department will communicate with the customer, explain the capabilities of the EMS, and understand the needs of the customer.  Sales will receive items from the customer – such as drawings and Bill of Materials – that are needed for the company to generate a quotation.

For new designs, the Purchasing department works with various component suppliers to obtain the best price with the shortest leads times for components that are used on a customer’s electronics assembly.

For existing designs, the department will place routine purchase orders to component suppliers so that the EMS will have inventory of the components needed to manufacture and assemble product for their customers.

The Purchasing department keeps abreast with when components will go “end of life” (or, obsolete) so the customer can be promptly informed.  They strive to give the customer options for obsolete components, based on communication with distributors and/or component manufacturers.

Process Engineering
Process Engineers are concerned with how an EMS will manufacture and assemble an electronic circuit board assembly for their customers.  They have a firm grasp of the capabilities of every piece of manufacturing equipment on the production floor, as well as a good grasp of the capabilities of equipment that exists in the marketplace.

During the quoting phase Process Engineers will determine if their existing equipment can be used to build assemblies for a new customer, or, must new equipment be purchased.  Since time is money, Process Engineers determine how long it will take to manufacture an assembly with existing equipment or with new equipment that must be purchased.  The Process Engineers’ time calculations are factored into the quote.

Quality Assurance (QA)
Individuals in the QA department strive to make sure that bad product is never shipped.  They do this by making sure that the company has quality controls in place all throughout the organization.  Just a few of the many quality controls they put in place include:

Incoming Inspection
The QA department will investigate defects with a manufactured assembly.  If they determine that it was due to a component problem from a supplier, they will demand the component supplier investigate why they supplied a defective component and ask them to create a report that discusses their findings and how they’ll prevent this problem from happening again.

Equipment Calibration
A company that does circuit board assembly will have various equipment (both electrical and mechanical) that must be periodically calibrated by the equipment manufacturer, or by a third-party calibration company.  Failure to perform calibrations on a regular basis, will likely result in either the equipment creating defects or the equipment not being able to detect defects.  Click here for more info on equipment calibration.

Production Operators
Production operators are the employees who build the electronic assemblies.  Among other tasks, they run the SMT machines, operate the test equipment, and pack manufactured units into boxes.

Test Engineering
Test Engineers are typically Electrical Engineers.  The job of a Test Engineer is to design hardware and software to functionally test a manufactured circuit board assembly to see if it performs according to the customer’s expectation.  For more info on what is meant by functional testing, see our article here.

Due to the plethora of machines, fixtures, and tooling needed in the manufacturing and assembling of electronic circuit boards, an EMS will have a highly skilled maintenance department that can repair broken equipment with minimal production downtime.  They typically maintain their own inventory of spare parts that can be used to make repairs.

Warehouse operations
Warehouse workers in an EMS perform 5 main functions:

  1. Receive materials off delivery trucks and place them into labelled storage locations.
  2. Pick parts from storage and place them onto a cart for delivery to the manufacturing floor to be used during circuit board assembly.
  3. Receive leftover parts from manufacturing and store them back into warehouse for future production use.
  4. Receive manufactured assemblies (also called “Finished Goods”) from the production floor and store in the warehouse for future shipment to a customer.
  5. Ship manufactured circuit board assemblies to the customer.

Design Engineers
Design Engineers are Electrical Engineers that have the capability and experience in designing electrical circuit board assemblies.  They also know how to do printed circuit board (PCB) layout.

It is highly advisable to work with an EMS that has Design capability.  On-staff Design Engineers are an excellent resource to tap into for the following reasons:

  1. Help make sure that a design is well-suited for manufacturing.
  2. They can help with scrutinizing a design to see if it could be designed with fewer or less expensive components.
  3. They can help with troubleshooting why a design does not function as expected.

Accounting, Human Resources, Customer Service, and IT
The job functions in these 4 areas of an electronics contract manufacturer, are very similar to those in companies in other industries.