PCB Assembly

Full Turnkey PCB Assembly Services: A Comprehensive Guide

full turnkey PCB assembly

First of all, turnkey means immediate service for the buyer. There are many types of turnkey assembly.

  • Full Turnkey PCB Assembly
  • Assembly only
  • Parts Turnkey
  • Boards Turnkey
  • Assembly and Parts
  • Rework

What is Full Turnkey PCB Assembly?

Full turnkey means full turnkey PCB assembly. It means the customer just provides files and the assembly house builds boards with assembly. Full turnkey PCB assembly includes quotation, purchasing, assembly, and fabrication. For a single purpose, we prefer full turnkey PCB assembly which is the best option for us. Additionally, a whole team of assembly houses complete the full turnkey projects very efficiently and smoothly. This single-source method saves time and money respectively. Usually, start-up companies easily get boards with full turnkey. Because it’s a cost reducer and a single service to serve whole things to customers, this service provides boards to customers in the shortest lead time.

what is full turnkey PCB assembly

Steps of Full Turnkey PCB Assembly

  1. Quote preparation and internal arrangement
  2. Purchasing boards and materials
  3. Making bare boards
  4. Assembly on bare board
  5. Final quality check
  6. Shipping

So here we discuss the whole procedure of full turnkey PCB assembly.

1. Quote Preparation and Internal Arrangement

A customer sent a whole order to an assembly salesperson to build full turnkey PCB assembly. So, the sales team sent those files to the sourcing and purchasing team to buy parts. Also, the sales team forwards those files to the fabrication house to provide board-making costs. The sales team is fully responsible for every communication between customers and them. The sales team is increasing the communication with the customer to expand work in the future. So this will be beneficial for business.

2. Purchasing Boards and Materials

The assembly house has collaborated with the PCB fabrication house to buy printed circuit boards.

This department works in both production houses. The assembly quotation team provides every cost of all parts needed in the customer bill of materials and its additional assembly requirements like class-3, rose testing, solder paste requirements, and all. The assembly quotation team sources all parts from different websites like Digi-key, Mouser, Avnet, Newark, etc. Purchasing teams have one type of customer ID which works on all electronic components shops to easily create the PO via different payment and shipping methods like card payment, cash payments, FedEx shipping, and standard shipping with extra charges. The fabrication quotation team provides every cost of board requirements like material, finish, class-3, flying probe, via-fill, etc. The fabrication purchase team purchases the material as per customer requirements. FR-4 and 370hr is standard material which is normally used by fab houses.

3. Making Bare Boards

Fabrication of house-making boards depends on board requirements. Drilling, etching, surface plating, and finishing, mask printing, silkscreen printing, AOI, routing, milling, and score its normal processes of fabrication to make boards. The fabrication house is truly responsible for matching the correct layout with the actual layout with critical layer requirements. After making boards in array and without array form boards are shipped to the assembly house in de-penalized or panelized form with packaging requirements.

4. Assembly on Bare Boards

PCB assembly means electronics are placed on the PCB with the pick and place machine. This pick and place has XY coordinates to place parts on the PCB with the exact location. Parts are loaded into the feeders of the pick-and-place machine. The parts come into the tape and reel and cut tape format. Then the production department sets requirements for which floor exactly is needed.

1. Solder Paste Printing

The solder stencil was printed on the PCB for the soldering. The solder stencil was inspected by the solder paste inspection machine. It shows some errors in the paste stencil if you have.

2. Pick and Place

3. Testing and Inspection
The next step is AOI. It’s one type of automatic inspection that inspects all PCBAs from different angles by using large-range cameras. It’s a contactless method. AOI is having a post-reflow for inspection. Post reflows inspect the PCB shorts, components damages, and missing solder for particular parts if any parts are damaged or faulty parts and other issues. Then it needs to be reworked.

X-ray machine provides a very effective solution to detect errors between solder joint connection, misalignment, and missing pads for BGAs.
ICT is used for incorrect rotations, values, and functionality of components like ICs, resistors, etc.

After ICT assembly boards go to flying probe testing to check all electrical connections in boards with the use of probes, it’s a very cost-reducing technique that production houses use commonly.

4. Cleaning
The most important part is cleaning the boards to remove irrelevant solder joints to remove shorts from the PCB. This cleaning method uses some water and various types of solvents. Most assembly vendors use deionized water to clean the PCBs.

PCB assembly on bare boards

5. Final Quality Check

This stage is very important for every order. Because the quality assurance department completes all documents regarding the project, all manual inspections are done at this stage. If any labels are required on boards then the final quality assurance department adds those labels as relevant. Final quality assurance also collects all shipping documents to fulfil packing requirements. If any boards do not meet quality requirements then it impacts on customer satisfaction. So ensuring all requirements are done or not its quality assurance department is the responsibility. If any boards fail then this team suggests to the production house how we sort out that issue so it does not happen again in the future to save cost and time.

6. Shipping

In this, ship all boards are in proper packaging as per customer request like bubble wrap, etc. Bubble wrap is the most effective packaging for all full turnkey PCB assembly vendors. Verify all documents are done as per the final quality assurance department. If all documents then all documents are attached with the whole PCBs. Then submit all boards to the customer address which is given by the purchasing team.
Advantages of Full Turnkey PCB Assembly

  • Easy to manage whole things
  • Bulky orders
  • All-in-one service (single-step service)
  • Cost saving is the most beneficial part of this method

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