UK Based Fabrication & Assembly Facility The innovation team brings many decades of well proven hard-won experience to the party. We can act as a seamless extension of your own development team or we can look after the entire end to end development process for you!
An online quotation can be obtained using the PCB Train price calculator. A single PCB is defined as the PCB area which is enclosed with one continuously cut profile line. The dimensions of the PCB should be entered as the length and breadth in mm of the rectangle which encompasses your PCB design. The actual PCB outline does not have to be rectangular
There are no additional tooling charges. There is a choice of solder resist or legend colour, materials, layer counts, copper weights, and thicknesses. Prices depend on the manufacturing lead time selected. The faster the service, the more you pay.
We recommend that your order is placed online. This ensures all the information we require is presented to us in one document.
We need PCB layer files in GERBER format plus standard CNC drill files (usually designated “excellon”). The default plot files from your CAD system are invariably suitable. ZIP them up and upload through our price calculator or just email them your order to us here.
You have a choice. Most customers want PCBs supplied as single circuits. However, you can order them as step & repeated panels. Either way, you send us a set of GERBER data with a single image and we do the panelisation.
Most customers will want their PCBs supplied as single circuits and prices can be obtained from the price calculator and orders may be placed online.
Simply provide us with single image PCB GERBER data. We will place your circuit in a “standard” panel in a format which we know to be acceptable for most automated assembly. Our standard panel design with handling frame has 2.00mm gaps between circuits with a 10.00mm handling frame on each of 4 sides. 3.00mm tooling holes and fiducial markers will be placed in each corner. Individual circuits will be fixed by 2.0mm tabs within the panel. During the “Quote and Order” process, select “Yes” to supply in panels. Enter the required number of images in the “X” axis and “Y” axes. Prices are still quoted as per circuit, but your order will be supplied in the specified panel arrangement. Note that the maximum overall step & repeated panel size should be no more than 200mm x 300mm, about the size of an A4 sheet of paper.
Customer designed handling frames present us with difficulties because of the wide variation in complexity. We recommend that you consider using the PCB Train standard handling frame for which there is no charge. However, if this is unsuitable, then PCB pricing will be based on the overall dimensions of your panel including the handling frame, plus an additional £100 charge for processing panel GERBER data or for creating the panel data from single image GERBER and your panel design. You cannot at present place this type of order online. Calculate the base order value from the website, add £100, and email your order details to us.
Solder paste data for step & repeated panels will be supplied upon request at no charge subject to solder paste layers having been provided within the original PCB data. email your request to us.
Pricing will be based on the overall dimensions of the panel. A multi-circuit panel is defined as a PCB which contains two or more different circuits on the same sheet. You design the panel and send us a single set of GERBER data. Multi-circuit panels can be extremely complicated. These types of configuration present problems for us during tooling and final profiling. There are extra charges if the lot price is less than our minimum lot prices for multi-circuit panels. We will manufacture multi-circuit panels at our quoted PCB Train prices but subject to minimum lot value of
| Layers | Price |
|---|---|
| 2 layers | £200 |
| 4 layers | £300 |
| 6 layers | £400 |
If your lot price is less than this, we will charge an additional lot premium of £10 for each circuit contained in one panel of your multi-circuit panel design. Remember to space the circuits at least 2.00 mm apart to allow for our standard 2.00mm router tool. You cannot at present place this type of order online. Calculate the order value from the website and email your order details to us
The design features of circuits must be within the PCB Train technical capability. We do not warrant to identify non-conformities in design files. Any impairment of functionality as a result of this is your responsibility. If your circuit falls outside the PCB Train technical capability, ask us for a special quote. We manufacture in a wide variety of materials and specifications. E-mail your requirement to PCB Train
FR4 laminate is the most common specification of copper clad laminate used to manufacture PCBs. The laminate is composed of an insulator made up of glass cloth, bound with epoxy resin and a flame retardant, between thin copper sheets. FR-4’s attractive properties include: low cost, high strength, low moisture absorption, and tolerance of the PCB manufacturing process.
The datasheets include these material parameters: Glass Transition Temp, Time to Delamination at elevated temperature, Decomposition Temp, Surface Resistivity, Dielectric Breakdown, Z-Axis coefficient of thermal expansion, Dielectric Constant, Dissipation Factor, Comparative Tracking Index (CTI), Peel Strength (1oz), Moisture Absorption, etc.
FR4 (150 deg C) middle Tg laminate Ventec VT-481TC/Laminate datasheet
This laminate is suitable for all single sided, double sided, & multi-layer PCBs & lead-free assembly operations with a middle range heat tolerance typical for FR4.
Applications for this grade of laminate include: Computers, Communication Equipment, Instrumentation, Electronic Gaming Machines, Automotive, etc
FR4 (180 deg C) high Tg laminate Ventec VT-47 Laminate datasheet.
This laminate is suitable for all single sided, double sided, & multi-layer PCBs & lead-free assembly operations with a higher range heat tolerance typical for FR4.
Applications for this grade of laminate include: Computers, Communication Equipment, Instrumentation, Precision Apparatus & Instruments, Servers, Routers, Automotive, Medical, etc
Polyimide (250 deg C) high Tg laminate Ventec VT-90H Laminate datasheet.
This laminate is suitable for all single sided, double sided, & multi-layer PCBs & lead-free assembly operations with a very high range heat tolerance.
Applications for this grade of laminate include: Chip Manufacturers, Engine/Flight Controls, Power Supply/Backplanes, Military and Burn-in Boards
Aluminium base copper clad laminate is commonly a thin sheet of copper clad FR4 bonded to a thicker sheet of aluminium which acts as a heat-sink. The bulk of aluminium clad PCBs are single sided SMD only circuits. The presence of a conduction layer of aluminium prevents the use of through hole components. The superior heat dissipation of aluminium clad laminate allows the design of smaller lower cost PCBs with thinner tracking, and denser component population than would otherwise be possible with standard FR 4 laminate.
This data provides information about: Aluminium thickness, FR4 dielectric thickness, Copper thickness, Overall thickness, Thickness tolerance, Thermal conductivity, Flammability rating, & UL file number. This data is frequently required by circuit designers.
Aluminium clad VT-4A2 laminate Link to specification and datasheet
Applications for this grade of laminate include: Power conversion, PDP, LED, Regulator for televisions, Monitor drives, Rectifiers, Power supply, etc
Controlled impedance is an advancement of Ohm’s law and relates specifically to alternating current circuits. Alternating currents are more complex and require higher levels of precision on the behalf of the PCB manufacturer. With direct current, only the resistance needs to be known to determine the relationship between voltage and current flow. With alternating current, voltages will be self-induced by associated current generated magnetic fields; that is to say, inductance. In addition, the voltage difference between conductors will create an electrostatic charge; that is to say, capacitance. Each individual track on a PCB will have a specific impedance value in relation to its neighbouring tracks or ground planes.
With high-speed digital signals, it can be crucial to predict and match the impedance of the transmission line (relevant tracks and ground plane) with the input and output impedance to minimise losses and reflections. Impedance factors are increasingly important as frequencies increase.
Manufacturing custom-made controlled impedance PCBs can be expensive. PCB Train’s circuit boards are fabricated as consistently as possible, and we use our technical knowledge to advise what feature widths (track widths and gaps) to use to achieve commonly required impedances. Because of this, our clients can receive the benefits of controlled impedance circuits without suffering the additional costs.
The number of possible transmission line structures is infinitely vast. Variables influencing the impedance are track width, insulation gaps, both in the “x, y” axis and “z” axis, the geometry of the transmission line structure, and the dielectric constant of the insulation material. We use intelligent software to design a test coupon of the same structure and impedance as that required within the final circuit. A time domain reflectometer (TDR) is used to measure the impedance of the test structure which is manufactured on the same sheet as the PCB. A digital microscope is used to measure the geometry of the structure. If the impedance of the test coupon structure agrees with the predicted value, then the reasonable assumption is that the similar structure in the body of the PCB will also have the required impedance.
This impedance information is published to assist users of the PCB Train service who are looking for a track impedance calculator to predict track impedance.
These guidelines relate only to PCBs fabricated on the PCB Train 4 Layer M/L 1.6 mm FR4 1 oz copper service. View the multi-layer build here.
Customers use this information at their own risk.
Layer descriptions are defined as follows:
Our calculations and measurements have established the following:
These guidelines relate only to PCBs fabricated on PCB Train 4 Layer M/L 0.8 mm FR4 1 oz. copper service. View the multi-layer build here.
These guidelines relate only to PCBs fabricated on the PCB Train 6 Layer M/L 1.6 mm FR4 1 oz. copper service. View the multi-layer build here.
All tolerances + / – 10%
If you require controlled impedance PCBs complete with measured impedance test coupons, please ask us to quote.
Immersion Silver is the standard finish on PCB Train and is RoHS compliant. It is an improvement on HASL being exceptionally flat, and can replace Immersion Gold over Electroless Nickel (Au/Ni) for most applications. The use of Immersion Silver has no effect on customer’s assembly processes.
Via holes and tracks within a BGA footprint must be entirely covered with solder resist. Failure to do so will cause solder to wick from the BGA pad during reflow resulting in failure of the solder joint. Similarly, do not put a via hole within a surface mount pad. Do not use the PCB Train Express service for designs containing BGA’s because this service does not offer a solder resist. All other PCB Train services include a solder resist as standard.
Avoid using blind or buried vias. The extra cost is only justified on specialist applications. A blind via is a connection that only goes part way through a PCB. A buried via is a connection that is completely internal in the multi-layer PCB. These types of vias are often suggested in text books as a way of routing more tracks in a given space, because they do not use board area on the layers that they do not penetrate. In practice, these techniques are rarely used for commercial application PCBs because of the high additional cost. An 8 layer PCB will often be cheaper than a 4 layer PCB with blind or buried vias. Blind & buried via PCBs are not a standard service on PCB Train but are available to special quote.
It is a golden PCB design rule to maintain uniform copper density across a track side and between track sides. There are two reasons for this. Firstly, copper imbalance will cause the undesirable bi-metallic strip effect of bow and twist. Secondly, it imbalances the thickness of copper plating in the electrolytic plating tanks because of differences in current density. This is another way of saying that the PCB will be under and over copper plated. The solution is to add copper planes to areas where there are few tracks. We recommend simple solid copper planes rather than hatching. Hatching by its nature, has lots of corners, and copper fragments can become detached at the hatch corners they have the potential to cause short circuits.
Standard default extended GERBER RS274X output will be fine for the tracking, solder resist, and legend layers. If possible, use “flashed pads” rather than “painted pads”. This reduces the file sizes, and assists with identifying net ends for testing Output all pads as “filled”, because that is almost certainly what you want, i.e. a complete solid copper pad, and not a thin copper outline for a pad. The standard convention is that all data is output looking down through the PCB from the component or top side. If this is not what you are sending us, please say so. This view is the same as you will see when you design the PCB. There is no need for you to mirror anything. A drawing showing how the layers build up in cross-section can be helpful. By convention, we treat one data-file as one PCB type designated by one PCB reference or name. If you have incorporated several different PCBs in one data-file, we will treat it as one (albeit complicated) PCB type. PCB data-files may be supplied step & repeated if you wish. If you have design notes, ZIP them up with the GERBER files in a README file PCB data-files must be compressed using PKzip before you upload them to us. The PCB Train website upload function requires data-files to be in .zip format.
he default drill file output of your CAD design software will be fine.
Your CAD design software will automatically name the layers of your PCB design output data-file. We are familiar with these outputs and you can just send us the default output.
We do not require electrical test data. Our test data is derived from the GERBER data of your design. When we receive your data, one of the first processes is to take a reference snapshot of the XY coordinates of the nets and their ends. After we have finished producing the PCB production tooling, we compare the production data “net ends” with the reference data “net ends”. They must be identical.
If possible, create component pads (= net ends) from flashed pads rather than painted lines. If painted pads are present, we have to convert them to flashed pads as part of the production tooling process. This is not just to generate electrical test coordinates, but also to reduce the data size. GERBER data is used throughout the production process, and smaller file sizes assist the speed of processing.
If you require electrolytic plating of gold edge connectors on your PCB design, this is not available on PCB Train. We can supply this type of gold plating to special quote. Ask us to quote specifically. Consider using a standard PCB Train gold over nickel finish, (ENIG or Au/Ni finish, 0.1 microns of immersion gold over 5 microns of electroless nickel). This finish is good for a limited number of insertions in the connector.
We are not talking about filenames here. What we are referring to is the benefit of physical marking the application of each printed layer in the PCB build-up. The purpose of this is to make it easy to quality check that your PCB has been built correctly at all stages of the production process. For example, the topside of the PCB should be marked as “trackside 1” for example. Or the bottom solder resist could be marked as “bottom solder resist” say. Similarly, inner tracking layers of multi-layer PCBs should be marked in sequence, for example, “inner layer 1″,” inner layer 2″, etc. Convention is that the 1st inner layer starts from the topside or component side. Although the CAD layout screen view will be through the PCB viewed from the topside, the layer description text should be mirrored in this view appropriately so the text is “right reading” when printed and viewed on the finished PCB component (think of the individual printing of inner layer pairs 1 + 2, 3 + 4, etc., and top and bottom sides).
It is bad practice to print legend ink on component pads. As part of our design rule checks, legends which may encroach on pads will be shaved back, and this may affect legibility.
The technical details are as follows:
We do not need a specific CNC rout file programme. What we do need is a graphic drawing showing the cutting line of the PCB profile. It is preferable to draw this on your screen with a zero-width line. If you use a thicker line, our working assumption is that the cut edge will be the centreline of the drawn line. Do not try to compensate for the router cutter width or try to show the cutter path. This is not necessary. Keep it simple and just show the actual cut line. Cut-outs and slots can be missed unless shown clearly in your drawing. It is good practice to annotate your drawing with text to indicate which areas are cut-outs and slots to avoid errors.
Our standard router is 2.00 mm diameter. The minimum radius of an internal corner will be 1.00 mm. The narrowest slot will be 2.00 mm. If smaller radii or narrower slots are required, draw our attention to this and ask us to quote specifically.
All solder resists are of the photo-imageable type, printed by direct mirror imaging without the use of photography. The use of automatic camera based fiducial registration gives superb line up of solder resist to copper pad.
Very often solder resist artwork will only physically line up one way with the appropriate tracking layer. However, it is very good practice to identify solder resist sides with appropriate text printed right reading when viewing the finished PCB, e.g. solder resist side 1, solder resist side 2 for example. We will check the solder resist clearances around component pads as part of our design rule checks, and increase them to our minimum if necessary.
Our recommended standard PCB finish is Immersion Silver (I.S.) This finish is flat and perfect for SMD assembly. It consists of an organic anti-tarnish layer over a thin layer of silver over exposed copper. The application of this finish imparts little stress on the PCB and the process has low environmental impact.
An optional alternative surface finish is electroless nickel immersion gold (ENIG). This consists of 0.1 micron immersion gold over 5 microns electroless nickel (also known as Au/Ni surface finish). ENIG is a more expensive process with a greater environmental impact than I.S.
The above finishes are lead-free (RoHS compliant), have excellent solderability and are ultrasonic wire bondable. They will withstand multiple reflow operations. They are both suitable for touch pad contacts.
Avoid finger marking any of these finishes as this may jeopardise solderability. All PCBs should be stored in a dry environment and kept wrapped up in order to extend their shelf life which will be a minimum of 6 months.
Be very careful with the design of PCBs which have some degree of symmetry. We strongly advise that some features are designed in on each layer which breaks up any symmetry. This will avoid any possibility of mirroring or miss-rotation of layers during fabrication.
