Steps to Place an PCB Order?
1. Introduction
The PCB industry requires PCB output files in gerber format. It is one of the popular formats for creating PCB output data. It is design engineer’s responsibility to create a valid data for his design: the interpretation of data on designer’s end and manufacturer’s end should unchanged. The PCB manufacturers have expanded their setups by introducing many other facilities alongwith manufacturing. Many manufacturers have proven them to be successful components procurement and pick-n-place PCB assembly service providers. A user may select his own choice of services from manufacturer. This article is mostly relevant to PCB manufacturing, the similar type of practices can be adopted for PCB Assembly etc.
2. Early Involvement of PCB Manufacturer
Since our several years of PCB design and manufacturing experience we always try to involve the manufacturer by the very first day. Why we do so? The reason is very clear that (perhaps) there may very few manufacturers who can manufacture every kind of PCB. There are many limitations such as engineering skills: like manufacturing of minimum track width/ clearance, minimum hole size and annular ring, types of vias, number of layers, impedance control applicability, availability of materials, finishing process, maximum yield per month, inspection class, PCB thickness control, packaging, shipment and delivery charges, and payment mode. All these parameters are narrated with slightly tighter tolerances are listed and mentioned in the “document for PCB quotation request”. We found it a good practice as manufacturer can better advice about his capabilities and material availabilities. The PCB design rules are defined according to parameters decided and communicated earlier except a few variables like maximum number of layers. A manufacturer involved in PCB design at an earlier stage can help to get rid-off from routing same PCB again and again.
3. Getting Quotations and Finalization
Once manufacture provides its skill set, then during PCB design process till the preliminary PCB design rule check, generally, there is no need to access the manufacturer anymore. After design completion, with respective quotation reference the manufacturer can be asked to re-evaluate his quotes or provide a fresh quote. The quotation acceptance is forwarded to the company senior engineers and payments department.
In general many manufactures have given online quotation calculators that take PCB files as input and country of origin and provide calculated online quotations instantly. The calculator adds one time setup cost, per PCB cost, packaging cost and shipping cost and other applicable charges.
A PCB manufacturer can provide quotations in different ways:
- The online instant quotation calculator is provided by almost all leading manufacturers. They have fitted charges formulas there to calculate a price quotation for given files. A workable quotation is on your desktop within a few seconds. An example of instant quotation calculator is shown in Figure 1.
Figure 1: An Instant Online PCB Price Calculator
- Another method is to get quotation of data by just providing PCB dimensional sizes i.e., form factor, material type, via size, and track-track clearance and track width, surface finish, solder mask color, quantity of PCBs, lead time, quotations validity, payment terms and conditions etc., etc. This is a rough quotation in the sense that there are many loopholes which may incorrectly interpreted by designer end or manufacturer end.
Figure 2: Sample Online PCB Quotation Calculator
A sample online quotations calculator is shown in Figure 2. Almost same method is adapted by manufacturer office quotations calculator.
- The third method is to send nearly finished data where PCB design is completed as per set design rules. A quotation is provided by manufacturer after carefully inspecting the data. If quoted prices, lead time, PCB material and other parameters mentioned in quotation notes are acceptable; the quotation is forwarded for engineering and payments department to kill any queries. This acceptance process takes a few days, in the meanwhile, PCB design is reviewed with consultation of assembly engineers. Final Gerber data is forwarded for manufacturing. It is also worth mentioning that, especially in foreign customer cases, many of PCB manufacturers work after receiving full advance payment. The same is not true for customers who have developed business relationships from a long time with manufacturers. The manufacturer mentions validity of quotations. The daily variations in financial market have impact on rise and fall of prices. So for financial acceptance this, validity of quotations, should be kept in mid.
4. Submission of Manufacturing Data
The manufacturers often have complains to have incomplete or insufficient manufacturing data forwarded from their customers. This practice wastes time of PCB fabrication lab engineer in inspecting input gerber data. An overlooked point like missing layer information, cutting boundary, boundary tolerances, via tenting i.e., via masking, material type, solder mask, thickness and other any parameters like theses in data may render into a garbage PCB. This is why complete note and detailed pcb layer stackup should merge into gerber files or attached in bitmap file. It is customer responsibility to submit accurate and complete data alongwith special fabrication notes (these should within manufacturer capability).
Figure 3: Sample PCB Fabrication Notes
The gerber data submission is step to start manufacturing. The gerber data is inspected by manufacturer fabrication engineer and then handed over to fabrication personnel.
5. Fabrication Queries
Leading manufacturers keep involved the PCB design engineer involved in manufacturing steps. Any confusions and data interpretation that needs clarification is immediately mailed to customer pointing out the area of interest. For example, components placed at the edges of PCB, solder mask and silkscreen placed over electronic components pads, multilayer pads with zero hole size, mechanical layers interfering with the signal layers.
The design engineer should understand the mentioned problem and clearly direct with his opinion otherwise manufacturer is free to apply his own expert practices. Generally, manufacturers do hard to complete their processes within mentioned lead time.
6. Summary
Although different personnel have different experience and practices however these are general guidelines for this activity. The above points i.e., answer to how to place an order for PCB manufacturing is summarized in a few steps below:
1- Complete your design; perform DRC by keeping in view to your required design parameters and manufacturer capabilities.
2- Ask a manufacturer for price quotation giving any fabrication instructions including shipment, payment other terms and conditions etc. For a price guesstimate the online instant quotation calculator can also be used.
3- Get financial acceptance from company management. Finalize PCB design reviews and engineering data. Put PCB version number and nomenclature over PCB (if required) and finish it. Furnish final data with special (if any) manufacturing notes.
4- Generate gerber files. Attach PCB layer stackup with complete pcb material ,pcb thickness details etc. Put data to manufacturer.
5- Answer fabrication queries during fabrication.
6- Guide manufacturer for shipment and acknowledge at reception of consignment etc.
