Get free PCB design and manufacturing tips from New Zealand's leading PCB experts, QualiEco Circuits
PCB design tips
Our team of experts from New Zealand and Australia has put together some tips to help you achieve PCB designs that are cost-effective and manufacturing-friendly.
Serving in Auckland, Wellington, Christchurch, Hamilton, Tauranga, Dunedin, Palmerston North, Napier and the rest of New Zealand
Follow these tips to create cost-effective and manufacture-friendly PCB designs.
PCB general tips
- In most cases it's advisable and convenient to use gerber in RS274-X (extended gerber) format. However, we do accept gerber in RS274-D format, which will require a separate aperture list/report file so we can fetch information about the pad and line sizes you have used to design the PCB. If the PCB has been designed in Protel/DXP/Altium Summer 09/Altium Designer 10 software, that’s fine. We can use .pcb or .pcbdoc files straight away.
- When ordering your PCBs please supply:
- Tool file/chart, telling us which tool is what size and how many of each tool is used
- Fabrication drawing or manufacturing requirements
- NC Drill file in ASCII format
- To ensure fast production of your PCB it's good to include a Readme file with the contact person’s name, phone/fax number and other information about your board requirements. This file can be in either ASCII (*.TXT) or Microsoft Word (*.DOC) format
- Please keep in mind that the following factors impact PCB assembly costs:
- PCB type (single /double /or multi layer)
- Laminate material (e.g. thicker than 1.6mm laminate and 1oz finish copper, Tg greater than 130 to 135 degree etc)
- Colour of solder mask and/or overlay (green for solder mask and white for overlay is our standard)
- Peelable Solder Mask
- Special surface finish like Immersion Silver, Immersion Gold or Immersion Tin. These finishes are used mainly to comply with RoHS and/or to achieve a flat finish for fine pitch components
- Extensive and very complex routing
- High number of slots
- High number of v-cut lines
- Controlled impedance
- PCBs that use high frequency laminates
- Plugged via
- We'll send you written confirmation of our commercial and technical acceptance within 24 to 36 hours of receiving your purchase order. This will confirm that we fully understand your requirements, and whether or not we can complete your request within your timeframe.
PCB design specifications
- For cost-effective manufacturing of your PCBs please ensure your designs include:
- Clearly mentioned cut mark. If possible use "keep out layer" or "mechanical layer". We measure PCB/panel dimension from the center of the cut mark. This means at the time of cutting, the outer edge of the router will fall right over the center of the cut mark.
- Continuous borderline, if the PCB is an odd shape. This will help us a lot in creating a rout program.
- Information about NPTH holes (in protel/DXP, click on the pad needs NPTH hole – go to "Advanced" menu and untick "Plated". While generating NC drill file from protel/DXP design, this change will write "NPTH" against that specific tool. Apart from this, it’s a good idea to create a separate tool for NPTH holes for better clarity.)
- Slot any information on the same layer where the cut mark has been specified. It is better to draw an actual slot shape in solid so the routing program is easy to generate. You must also state whether slots required are PTH or NPTH.
- Any relevant information that helps the manufacturer to understand your design requirements. This may include drill drawing, information about PCB type, PCB material, copper-solder mask-overlay requirement, tool table (if possible) and any other special requirements. For example, high Tg laminate, gold platting, peelable solder mask, flood coat, different colour of masking or overlay, allowable tolerances, manufacturing standards etc.
- Break off tab locations, if placing tabs at any particular position can cause problems when breaking boards apart after assembly.
- When designing a PCB, try to limit the amount of draws you use. Draws use a lot of memory and slow the programming time. Use a flash for pads instead of draws. If for some reason we need to increase or decrease that pad size, it can easily be done by changing the D-code but if they are done with draws it could be a nightmare.
- If you are using old protel (DOS version), keep in mind that it restricts font sizes to 36, 48, 60, 72, 84, 96, 108 (all sizes are in mil i.e. thou). Let’s say if you have used font size 39 thou, it changes that particular font to 48 thou - one step higher in rank when we generate gerber data out of your protel document. This can create shorts if any font has been used in the copper layer and increasing in size may cause it to touch nearby track or pad.
- Using hexagonal pads in protel software (specially Protel 99 and earlier versions) isn’t advisable, because while generating gerber data from a protel document it can cause two major problems: (1) Rotating hexagonal pad, which can cause a short if any track is close (2) Hexagonal pad size changes to the smallest size of the hexagonal pad, if more than one size of hexagonal pads have been used. We have found a way to get rid of this problem but it is always better to avoid it in the first place.
- It has been noticed on a few occasions that overlay font has been rotated 90 degrees while generating gerber from DXP. Unfortunately it isn’t possible to detect this error unless an engineer doubts the overlay structure. No remedy to this error has been found so far so if you know more about it please let us know and we’ll post your suggestions for everyone's benefit.
- Ensure that no silkscreen falls on any pads or mask opening. This could affect the bare board testing and soldering process. We have specialised software to clip such overlay text at our end. As a rule of thumb, clipping should be done in such a way that 0.1mm area is clear around the solder mask pad.
- If routing is required, make sure the nearest copper area (i.e. pad, track or ground) is at least 0.3mm away from the center of the cut mark. In the case of v-grooving, at least 0.7-0.8mm clearance would be required.
- Add some text to the copper layer wherever possible. This will help the CAD engineer to identify top and bottom copper in case of any confusion.
- If your design is sensitive and contains an isolation barrier, please tell us when placing your order. That way we can make sure no copper is accidently placed in the form of date code or any other way.
- At the time of making prototypes, try to design the PCB as if you are finalising design for production. This will save you extra set up costs if the prototype turns up in production without any changes. This relates mainly to designs that are into panel form – effective panelisation at the first instance can save a lot at the time of normal production.
- Version control is very critical to anyone who deals with various modifications. It is better to add "R1" or "V1" suffix after the PCB description to identify the most recent design. The moment you realise that the old version is of no use, inform us as quickly as you can so we can discard the complete record and artwork at our end. This can save you from our purchasing system generating an order with an old version by mistake.
- Protel keeps new dates on record even if you simply view your designs without editing them. Therefore it is hard to decipher the most recent design just from the date of modification.
We hope these design tips will help you create PCB layouts that are easier and cheaper to manufacture.
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We have the capability to manufacture and assemble Single Sided/Layer (SS), Double Sided/Layer (DS-NPTH & DS-PTH) and MultiLayer (up to 32 layers) PCBs with RoHS as an option.
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We can manufacture and assemble Single Sided/Layer (SS), Double Sided/Layer (DS-NPTH & DS-PTH) and MultiLayer (up to 32 layers) PCBs with RoHS as an option.
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QualiEco Circuits Limited is an excellent supplier to us! We appreciate the quality of service and support that we receive from QualiEco Circuits. They always deliver what is promised
For printed circuit boards (PCBs) or PCB assembly you can count on. Talk to the friendly and experienced team at QualiEco Circuits, New Zealand.