Basic technical conditions

EXTENDED GERBER RS274-X
- if your design system allows it, use the extended gerber RS 274-X to export data. Its main advantage is that it carries all the information about shape and size of apertures in the file head. Data import is easier and a possibility of erroneous editing of apertures is minimized. Also the time for processing data is shortened significantly, which also influences lower price of data preparation.

specification Gerber RS274-X

more info : technologie CAD/CAM

WORKING FILES
-if customer requires returning production files for approval or archiving, we send them after processing the data in gerber format, or on request in PDF or CAM format. If the files are required for approval, the printed circuit is not produced until the data is confirmed. The following rules are for confirmation:

prod.time     max time for confirmation
upto 3 WDs  /  1 hour
upto 5 WDs  /  2 hours
upto 8 WDs  /  4 hours
8WDs and more  /  6 hours

*** Valid for standard production and in working hours 8:00-16:00
*** If max time for confirmation will not be matched, production time may be shifted according to current production load.
*** If customer requires change in production files, which was not noted in order, it is necessary to prepare production files again and proportionate part of costs may be charged. Also production time may be shifted according to current production load.

CUT-OUTS AND OUTLINE ROUTING
- please always state the requirement for routing of inside cut-outs, grooves or outline in your order, in appended informational files or in the routing draft.
more info : contour fabrication
special holes

SEPARATION OF V-SCORED PRINTED CIRCUITS
- if you separate V-scored printed circuits manually, you should arrange setting of a deeper groove with the technician of the order reception. The standard thickness of residual material for grooved panels is 1/3 of the total thickness of the material. This setting is suitable especially for division of individual patterns by a special tool.
more info : contour fabrication

HOLES WITH SOLDERMASK
- because of still smaller component base and therefore still smaller and smaller vias and pads size, occurs when masked vias accidental accumulation of charge on the surface of the PCBs and subsequent nonplating of final chemical processes. This causes poor quality of the final surface, which we cannot influence in different way than unmasking of the via. It can also lead to the closure of chemistry inside vias (typically etch chemistry or chemical finishing) which, over time, can decrease the reliability of the via. For this reason, all vias on boards with chemical final processes will be both sides unmasked in the CAM operations (hole diameter + 150um/200um for chemical gold and HAL/chemical tin). If the customer does not agree with this, it must be specified in the order or specification and at the same time customer takes the risk of poor quality of the final surface associated with masked vias.

If you necessarily require masked vias, then we recommend to use on the necessary holes so called via plugging or via filling + overplating (IPC-4761 type IIIa or VII).

LEGEND PRINTING OVERLAPPING SOLDERING PADS
- if the legend printing overlaps the pads, it is as a standard adjusted by trimming. If it contains information about shapes and values of the parts, after cutting it often becomes unreadable. If we did not adjust the overlapping decal, it would subsequently render impossible electrical testing and wave soldering. Therefore you should consider using only the shapes of the parts in these cases.

MIRRORING OF LAYERS WHEN YOU EXPORT DATA FROM DESIGNING SYSTEMS
- when exporting layers and drill data from your system, please check whether you have used mirroring in some layers. At one sided PCB that causes complications in data processing, because the signs remain of the original layers (eg. * .sol - Bottom layer - BOT), but in fact this is the layer you already mirrored and is at the moment TOP layer - upper. If some layers are mirrored, it may be on the board as it was exported - mirrored as well. Please send the data as it was designed, without any mirroring. And looking at the component side. If yu are not able to export this way, please consult with us or let us know in your order or readme.txt file.

BALANCE OF COPPER
- we strongly recommend to use balanced copper on pair layers, through middle of the board and also on each layer. If you don’t do so, we cannot quarantee bow&twist of 0.75% according to IPC-A-600. It is enough if you use cipper thieving on unbalanced layers.

more info : copper balance

- The PCB stackup can be more or less freely combined from the available materials, but should always be symmetrical across the centre.

SOLDERMASK
- for green soldermask is the smallest residual bridge 100um, for other color 135um. Bridges that are less than 100um to hold PCB and will therefore automatically removed during processing, to their reproach does not cause problems in the production and PCB assembly. The smallest overlap of solder mask of the pads against it 75um.

ARCHIVING OF PRODUCTION DATA
- you may store the film data for production for free in our archive. Film matrices are stored in clean and air-conditioned rooms with automatically controlled temperature ( ± 0.5°C ) and humidity ( ± 3 % ). Here the films are kept under the same conditions as at the workplace of the photoplotter and thus their longer life is secured. For each client there is an individual database in the computer, which enables to observe not only the current state of the archived films but also their age and the number of the cycles of exposure. This assures exposure of the pattern always from high-quality and flawless matrices in future production.

EXPORT OF DATA FROM THE PROGRAMS AUTOCAD AND CORELDRAW
- if you use only graphic programs such as AutoCAD or CorelDraw to create a design of a printed circuit, use the format *.DXF. Simultaneously with these files, send also a preview of the printed circuit in an optional format (preferably "JPG"). The preview serves to check the sameness of the pattern after the transfer of the "DXF" format into gerber files for the photoplotter.

ONE-SIDED MASKED VIAS
Each drilled hole in two and multilayer printed circuit boards must be clearly unmasked (PTH component) or masked (mostly VIAs). If the opening is masked on one side only, there can rest some dirt or rests of manufacturing chemistry, which can cause poor quality finishes in its vicinity. These are either unplated or flakes of plating on the plated surface. The surface can also be colored differently. Unfortunately, these holes can not be simply found on our side therefore this is customers responsibility to check this.

TECHNOLOGICAL FRAME IN MULTIPANELS
- printed circuits delivered in multipanels (V-scored, routed on bridges) come with technological surroundings requested by the customer. If not, they are delivered with our standard galvanic frame. But some assembling companies require exact technological surroundings and our galvanic frame does not suit them. Please check with your supplier what technological surroundings you really need, we will certainly adapt to your needs.
more info : contour fabrication

PRINTED CIRCUITS WITHOUT A PROTECTIVE SOLDER MASK
- printed circuits with fine patterns (5. and higher construction class) are not suitable to be delivered without a protective soldering mask. The technology of heat metallizing H.A.L. can cause overblows of tin and thus micro-short circuits, which are hard to be found and hard to be removed without electrical testing. As a substitute, you can take advantage of the technologies of chemical tinning or copper passivation.

RECEIVING A FINISHED ORDER
- if you require sending the finished PCBs by post or by another shipper, please always mention it in your order. Our standard is to send by post to the clients outside of Prague, the Prague clients are supposed to collect their order personally if they do not state the way of transport. The date of finishing the production means the day when the finished order is handed over to the first shipper.

CHANGE OF THE PATTERN AND ITS CORRECT MARKING
- with the change of the pattern of a printed circuit and necessity to draw new film data, please mark the printed circuits either by a new name or changing of the revision (rev.B, rev.2 etc....). Our system checks identical names for the same client but it is not infallible. By a new noninterchangeable marking, you will avoid a possible mistake and transfer from the archive into the production of an older, out-of-date version.

THE RISK OF PLACING THE PATTERN NEAR THE PCB OUTLINE
- a great risk for finishing procedures (V-scoring, routing, cutting) is a placement of parts of the pattern near the edge of the board. For the outline worked by cutting, the minimal distance of the pattern is 1mm from the edge of the board, for V-scoring it is 0,25mm and for routing 0,2mm.
more info : contour fabrication

PCB DRYING BEFORE ASSEMBLY
- we always recommend drying the PCBs before assembly to reduce moisture in the laminate. This will prevent many problems with PCB seating, functionality or reliability. Recommended drying conditions can be found here : drying the PCB before assembly

THE SYSTEM OF INQUIRY / OFFER
- you can download orientational price lists of printed circuits on our webpage. For exact determination of the total price of the whole order or for more complicated requirements, please take advantage of our system of inquiry / offer on . For serial amounts, we calculate special, negotiated prices which you will not find in our price list. If you use our price offer, please state its number in your order.