PCB Engineering Questions

Reason of failed review:

The parameters in gerber files/PDF/readme/word and so on are not same as the order details online.

The parameters include soldermask/silkscreen coulor ,TG ,surface finished ,boards thickness ,finished copper thickness ,gold fingers ,materials and so on.

For example:the boards thickness customer choose online is 1.0mm ,but below texts in gerber files show as 1.6mm.Then AlteraFlex will send email to customers and check which one is right.

Reason of failed review, there are 4 reasons.

A: The board size is less than 75*45/75*75mm.

B: The v-cut lines are not straight and through the whole board.

C: The spacing between the V-CUT lines and copper lines is less than 0.4mm.

D: the boards thickness is under 0.6mm.

Suggestions:

A: The board size in direction for V-CUT lines should be 75mm at least,the other side which don't do V-CUT should be 45mm at least.If there are V-CUT lines in  X and Y direction ,then the board size should be over 75*75mm.

B: The V-CUT lines should be straight and through the whole board.

C: The spacing between the V-CUT lines and copper lines should be over 0.4mm to avoid damaging the copper lines.

D: The boards thickness which can do V-CUT is over 0.6mm.

E: If the 4 items can't be fixed ,the V-CUT lines can be deleted and ignored  or  the boards can arranged in our high precision factory to do ,the price will be different.

Reason of failed review:

A: The Space between IC pads should be at least 0.2mm if solder mask bridge for green soldermask needed of 1oz/2oz/3oz copper board.

B: Space between IC is smaller than 0.22mm, we can not do solder mask bridge for blue/red/white/yellow/black/matte black solder mask of 1oz/2oz/3oz copper.

C: For 3oz ~10oz copper, if solder mask bridge is needed, IC pad width and IC pad spacing should be ≥ trace width and trace spacing corresponding to copper thickness. For example, for 3oz copper thickness board, trace width/spacing should be ≥ 0.25mm/0.23MM. Then IC pad spacing should be at least 0.23mm, so that  solder mask bridge is available.

Suggestion:

A: Modify the space between IC pads to reach our standard.

B: Just do as your file and accept no soldermask bridge between IC pads.

Reason of failed review:

Vias process of design is different from online option. From below screenshot, you may see there are some drills overlapping slots, because of different shape and size of them, so it’s necessary to confirm should we make according to drills or slots.

Suggestions:

The best way is to avoid this in design, but if you are unsure about this, can just add special note “ Once drills overlap slots, follow drills or slots”, which can speed our reviewing of design up.

Reason of failed review:

Screenshot shown as below, you may find the outline vertical are very thick, we need to confirm the final dimension of PCB should be subject to the inner, outer or the middle of the line.

Suggestions:

Better not design outline in shape of routing/milling  and without consideration of diameter of router, but just draw as horizontal line shown as below,the middle of the outline will be measured for the boards dimension. If cannot control this in design, then just clarify the final dimension online when you create order online.

Reason of failed review:

The layout of PCB is unclear, if the layout of PCB is unclear, we will make PCBs wrong.

Suggestions:

Two cases normally

1. There are multiple outline of PCBs at same layer or different layers such as GKO and GM1, please delete the redundant outline of PCB or add special note “ Outline is GM1 or GKO or something should be”.

2. The outline is incomplete, screenshot shown as below, you may find the outline is almost done but lack the left part, it’s hard to tell if the shape should be regular or irregular with special notch or something else, so better to complete the outline and resubmit the complete file online again for checking. Some customers will just draw four corners of design, if it’s okay to just complete the outline on the basis of those four corners without any notch bust just straight line, then you can add a remark when create order online.

Reason of failed review:

Solder mask layer is opening entirely, If make according to below solder mask layer directly, the boards will be opening entirely without any solder mask to protect the boards.

Suggestions:

It will normally occur after generate Gerber file from Eagle, to avoid such issue, please make sure to cancel the tick of” Nagative Polarity” when generate solder mask layer. For details, here is the URL for your reference.

Reason of failed review:

There is no board outline/ copper layer/solder mask layer /silkscreen layer/NC-drill file in gerber files. But the order details show these layers are necessary and no any remark to clarify them.

Suggestion:

A: There is no board outline, pls add board outline layer in your gerber files,because board outline are defined  the shape and size of pcb.

B: If there is no solder mask layer/drill file/silkscreen layer, pls choose online parameter as “none”

C: If there is no copper layer, pls note which copper layer is empty when you place order.

Reason of failed review: 

For your panel file, it has distance between pcbs. And the distance is smaller than 1.6mm. Pls check and tell us which one we should follow: 0mm V-Scoring, 3mm V-Scoring or Tab Route.

Normally, for the panel, it has V-Scoring and Tab Route.

For V-Scoring, it has 0mm distance V-Scoring and 3mm V-Scoring between pcbs.

For tab route and stamp holes, it can used in the irregular boards. However, for tab route, the space between boards should be 1.6mm. 2mm is the default value.

Suggestion:

1. If there is no component out of outline and the outline is regular shape, we suggest to  choose 0mm V-Scoring.

2. If it is irregular shape, we suggest to choose Tab Route;

3. If you need distance between pcbs, we suggest 3mm or Tab Route.

Reason of failed review: 

Normally, for 1 order, only 1 gerber file is needed. But in your file, there are several gerber files.

Suggestion:

1. Do you want us to make panel of these files? If so, do you have any demands of panel? Do you accept the X-Out Allowance in panel(Bad pcbs exists in panel)? We will mark “×” on bad pcbs.

2. Do you want us to make different single pieces? If so, next time, we suggest to put several pcbs orders. We can combine shipping and they will be in 1 package.

3. If only 1 gerber file is needed, pls check and tell us which file is correct one.

Reason of failed review: Your solder mask layer is empty. Or there is no solder mask in your gerber file.

Suggestion:

1. If it is correct, do you want us to cover solder ink on whole pcb ?

2. Do you want us to make whole pcb open and no solder ink in pcbs?

3. If it is incorrect, pls update your file and send it to us.

BTW, we suggest you can write details on “other special request” so that we can avoid same problem. Eg: whole bottom side should be covered with green ink

Reason of failed review: 

In your file, it has the demands of stackup. But you didn’t tick the Custom Stackup in Additional Options. We need to confirm which one we should follow.

Reason of failed review: In your panel file, it is panel as tab route. For tab route, the space between boards should be 1.6mm. But in your design, the distance of tab route is smaller than 1.6mm.

Suggestion:

We suggest to broaden it to 1.6mm and add stamp holes. It is easier for you to take pcbs apart

Reason of failed review:

The v-scoring line/slot requires to be in one separate outline layer rather than on copper/silkscreen/soldermask layer. Otherwise, they might be regarded as copper/silkscreen/soldermask and will not be made out as v-scoring line or slot. 

Suggestion:

Please design the v-scoring line/slot in one separate outline layer.

Reason of failed review:

According to our prototype factory's production capability, the diameter of BGA pad (round one below) should be at least 0.25mm, the space between copper trace and BGA PAD should be at least 0.15mm, BGA to Pad should be not less 0.15mm(1OZ complete copper thickness),BGA Pad to BGA Pad should be not less 0.35mm.

AlteraFlex advanced PCB factory can now manufacturing abilities:

The minimum diameter of BGA is 0.2MM (the sample limit can be 0.15MM), the minimum BGA to line is 3MIL (the prototype limit can be 2.5MIL), the BGA spacing limit is 0.4mm, and the conventional 0.5mm

Challenges to the limit are not easy to produce, because the scrap rate is too high, resulting in increased costs.

Suggestions:

You can update the files and resubmit online for checking again if it’s okay to design according to above capability, but if it’s necessary to make such as 0.2mm BGA or something else over our standard requirements above, it’s free to contact your own sales to quote from our high-tech factory.

Reason of failed review:

Design has no silkscreen layer but online is yes with silkscreen.

Suggestions: There are three cases normally, the silkscreen is added to other layer such as solder mask or copper layer, then the option online should be still no, because the silkscreen layer here we talk about is only for silkscreen layer not just legends. Secondly, if the design should contain silkscreen layer, then please update and resubmit it online for checking again. Last one, the silkscreen layer is not needed, then please choose “ None” online.

Reason: The file is 1-layer board, while you choose "2-layer" in the ordering process at AlteraFlex (or file is 2 layers boards, but you choose 1 layer on AlteraFlex). We need the online specifications to be in accord with the gerber file to proceed.

Suggestion:

A: Please note correct for copper layer, solder mask layer and the silkscreen you need for single layer board. For example: top copper layer, top solder mask layer, top silkscreen layer.

B: If you have plated holes design, the boards need to be made as 2 layers board.

We can add some pads on the copper layer to make it as 2 layers board.

Reason: The minimum diameter of castellated holes is 0.6 mm and the minimum distance between two Plated half holes is 0.55 mm. 

Suggestion:

A: We suggest you to design the distance for the castellated holes to be 0.6mm and the gap to be 0.55mm.

B: If the gap is only 0.5mm and you can not enlarge it, the board can be made in our high-precision line for production.

Reason:

The distance between the trace and board outline should be 0.25mm for us to proceed. 

Suggestion:

A: Enlarge the outline to meet the space.

B: If the size is smaller than 0.25mm, we will cut the copper.

C: If the size is smaller than 0.25mm, we will move the trace a little to keep the distance between the trace to the board outline to be 0.25mm

Reason:

The vias cut the copper trace. It might cut the trace off and cause open circuit, better to move the drill away from trace.

Suggestion:

A: Correct the gerber file to remove the hole in the trace.

B: Note”There is a hole in the trace. Just make as it is” when place the order online.

Reason:

We cannot confirm if you need plated edge to be made or not according to your design.

Suggestion:

A: If you need to do edge plating, pls choose it when you order online, also it is better that sign the edge plating position in your file, like the following pics shows.

B: Ignore the pad that is out of the board outline. Just make those inside the board outline. There will be some burrs around it.

C: Cut the copper in the fabrication. The distance between the copper and board outline will be enlarged to 0.25mm.

Reason of failed review:

Normally, there are only 1 top silkscreen layer and 1 bottom silkscreen layer in 1 gerber file. But in your file, there are 2 top silkscreen layers.

Suggestion:

1. If both top silkscreen files is needed, pls tell us. We will combine them;

2. If only 1 file is needed, psl advise which one we should follow;

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BTW, next time, you can write “only 1 top silkscreen is needed, it is ***** layer” or  “there are 2 silkscreen files are needed, there are ****+****” on the other special request to avoid the same question.

Reason of failed review:

The slot requires to be in one separate outline layer.

Suggestion:

1. You can add some remarks in other special request to make it clearer for us to check. Eg: GKO/GM1 layer shows the slots.

2. You can rename this layer as “slot” or other name for clarification.

Reason of failed review:

You’ve remarked “UL marking, Date Code” in your file, but you haven’t chosen UL Marking in additional option or remark it in other special request.

Suggestion:

Please choose the UL Marking you need in additional option. If you need to add date code(WWYY), please add one remark in other special request.

Reason of failed review:

There’re some legends on copper layer. It might be something wrong when you generate this file.

Suggestion:

After generating gerbers from other files, please use our online gerber viewer to double check it before upload it at our system.

Reason of failed review:

You’ve chosen gold fingers and beveling at our system. But there’s no gold finger design inside.

Suggestion:

Do you need gold fingers? Or we can just ignore this option?

Reason of failed review:

The drills might hurt the circuit, please revise your file.

Suggestion:

After generating gerbers from other files, please use our online gerber viewer to double check it before upload it at our system.

Reason of failed review:

There’s no drill file inside. Would you like to change to no drill?

Suggestion:

If you don’t need drills in your file, you can choose no drills at online quote.

Reason of failed review:

There’s one legend on every layer. It might be something wrong when you generate the file.

Suggestion:

After generating gerbers from other files, please use our online gerber viewer to double check it before upload it at our system.

Reason of failed review:

For the beveling of gold fingers, it would be better leave soldermask opening for the whole gold fingers part. Otherwise, the beveling might be warped and burred. Can we enlarge the soldermask opening part for it?

Suggestion:

If you need the beveling of gold fingers, please kindly leave soldermask opening for the whole gold fingers part. So that the beveling will not cause warps and burrs.

Reason of failed review:

Please find the attached pic. The drill table you remarked in your file is not fitted with drill file. Can we just ignore the difference and proceed with the drill file?

Suggestion:

Please kindly check your drill file and the drill table remarked in your file. Otherwise, it might be confusing for us to check.

Reason of failed review:

The BGA pad opening is smaller than the copper layer pad, we need to confirm if it according to the copper layer pad to open or you need to revise the file.

Suggestion:

The solder mask pad opening needs to be larger than the copper layer pad 2—4mils.

Reason of failed review:

There are 4 corners parts are overlap with the board outline, we couldn’t confirm the 4 corners parts if they need to be cut out, it will cause the board outline finished is different.

Suggestion:

1.  You can design the board outline with radian directly.

Pls delete the extra parts to make the board outline clear.

Reason of failed review:

The holes will cut out the copper layer of vias, we couldn’t confirm if it is ok for you?

Suggestion:

1. If you don’t need to do the vias, pls delete it directly when you design

If you need to do the vias, pls keep a spacing between holes, the hole spacing usually is 0.2mm 

Reason of failed review:

There is only one solder mask layer, in your file, we couldn’t confirm how to do the another solder mask layer.

Maybe the top and bottom solder mask layers are same, maybe the bottom solder mask layer is less, maybe there is no bottom solder mask layer, it will consider if you need to do cover with the solder mask ink all or not.

Suggestion:

1. Pls design complete top and bottom solder mask layer in your file even it is same.

2. Pls note how to do the bottom solder mask when you order online:

• Use the same solder mask layer as top side
• There is no bottom solder mask layer, pls cover with the solder mask ink all in the bottom side

Reason of failed review: If there is no D-code, the copper or pad or holes will be without shape and size.

Suggestion: Pls revise the file then make the D-code is complete. If the D-code is not useful, pls delete them to make it clear.