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EDA => General PCB/EDA/CAD Discussions => Topic started by: hal9001 on April 29, 2021, 07:09:48 am

Title: JLCPCB V-cut Support for Assembly?
Post by: hal9001 on April 29, 2021, 07:09:48 am
Has any one had experience getting a V-cut panelized board assembled with JLCPCB? Their fabrication page shows they have V-Cut capability as "Panelization without space"
(https://www.eevblog.com/forum/eda/jlcpcb-v-cut-support-for-assembly/?action=dlattach;attach=1215434;image)

But their assembly page says
Quote
Please panelize your boards with stamp holes, V-cut panels are not supported currently.

Why would assembly not have v-cut capability?
Title: Re: JLCPCB V-cut Support for Assembly?
Post by: DIYGUY Chris on April 30, 2021, 02:27:50 am
Hi
Please check the manufacturing steps of the PCB manufacturer and you will learn why it is recommended to use Mouse bites (stamp-holes) method when you create a Panel for assembly.
It is the fact that V-cut lines and profiling comes after assembling the parts so in order to avoid any damage on the electronics side of the assembled boards it is recommended to use the stamp holes since drilling is a step performed before the PCBA step.
Title: Re: JLCPCB V-cut Support for Assembly?
Post by: hal9001 on April 30, 2021, 04:36:16 am
Hi
Please check the manufacturing steps of the PCB manufacturer and you will learn why it is recommended to use Mouse bites (stamp-holes) method when you create a Panel for assembly.
It is the fact that V-cut lines and profiling comes after assembling the parts so in order to avoid any damage on the electronics side of the assembled boards it is recommended to use the stamp holes since drilling is a step performed before the PCBA step.

I thought assembling was last in the manufacturing. Thanks for the clarification.
Title: Re: JLCPCB V-cut Support for Assembly?
Post by: Shadowfire on May 02, 2021, 07:11:39 pm
I used to work at a small contract manufacturer.  Here is the process (for a surface mount board)
1. Panelized PCB is received from the PCB manufacturer.  A visual inspection is performed and bad panels (which have been marked by the PCB manufacturer) are noted.
2. Panel and stencil are loaded into the solder printer.  Solder is applied to the board.  (Solder is applied to all boards in the panel, even the bad ones).
3. Panel is visually examined to make sure that solder application is correct (no missing pads, insufficient solder, smears, etc); if there are problems, any issues are addressed, and the board is washed free of paste and re-stenciled.
4. Panel is loaded into the pick-and-place machine.  The operator will tell the pick-and-place machines which individual boards are to be populated (i.e. disables any boards noted in step 1's inspection).
5. After the parts are placed, the board is visually inspected to make sure everything is aligned properly in the pads.  (Things like polarity of the diodes are fixed in the first-piece inspection process).
6. The board is run through the reflow over.  All the components are soldered in place.
7. The board is inspected to make sure that nothing exploded, flew off, or tombstoned during reflow.
8. If there are components on the back side of the board, the board is re-stenciled/placed/reflowed on the opposite side.  (Note that this can preclude some tall components on the top side from being installed during pick-and-place and force them to be a secondary operation).
9. The board is washed in a board washing machine.
10.  If the board is panelized, now is when they are split apart.  We had a special manual "saw" for cutting out V-grooved panels (the saw wheel looked more like a pizza cutter than a traditional saw blade).  Therefore, any part that you have on the panel which is at or crosses the edge of the board, will be a secondary operation (and cost more).
11.  Any required secondary operations (installing through hole components, board edge components noted above, etc) were done.  If soldering was required for the secondary operations, the boards were washed again (unless the components couldn't survive the wash, in which case no-clean flux soler was used).
12.  Panels were tested with the test jig and test procedure.
13.  Fallouts from the test procedure were sent to a repair technician for diagnostics, identification of any manufacturing issues, and repair.
14. Completed PCB's had appropriate serial numbers applied.  (If you were just ordering finished PCB's, the process stopped here and the boards were shipped out)
15.  Any other final assembly steps (installing board and other product case assemblies into product case, ultrasonic case welding, engraving, etc)
16. Retest of final product.
17. Packaging of final product (thermally/ultrasonically welded plastic antitheft packaging, boxes, foam, instruction manuals, ESD bags for bare boards, etc)

Through hole boards are similar, but they don't get stenciled/pick-n-placed.  Instead, they are run through a machine which automatically installs, clinches, and cuts the leads of the through hole components; the boards are then inspected, and then run through a wave soldering machine instead of a reflow oven.
Title: Re: JLCPCB V-cut Support for Assembly?
Post by: Max2018 on June 22, 2021, 02:55:28 am
A little bit late:
My guess is they take the entire panel and do the final routing after assembly which would explain why they can't offer v scoring.
If you take a close look at the boards they deliver you will notice that the board edge isn't smooth/has indents alongside the edge which are very likely mean it was routed twice.