Ordering Boards

2016-03-25 23:40:38 chip Page 1616 📢 PUBLIC

I am beginning to see the light at the end of the tunnel... The machine has been configured and calibrated, it has built 3 mock boards in a row without a problem, and I am now running the machine at 100% production speed. It is fun to watch the machine run at full speed.

It is time to order the actual boards and stencil. It is now 4:45pm on Friday afternoon before a holiday weekend -- there is no advantage to rushing the order in at the last minute. Instead, I will take time to carefully review the design and place the order on Tuesday morning. Ordering the boards is crossing the Rubicon, correcting mistakes costs real money after the order has been placed.

Bay Area Circuits has low-cost bundles. 3X 2 layer board (up to 50sqin) for $90, 4 layers for $180. My board is 3 layers -- I wonder if I can split the difference? I called BAC and learned that from their perspective, a 3 layer board is exactly the same as a 4 layer. No price break. $180 is the minimum order, so no price break for an extremely small board (6sqin) either. The minimum order is 3 boards for $180.

NOTE: A 4 layer board is no more expensive than a 3 layer board, so if the design won't fit in 2 layers I should bump it to 4 layers.

This is an unproven board; I don't want to invest much money into it until I am sure there are no layout or circuit errors. The thermal layer does not provide any electrical connections, so I can omit it without any layout changes or loss of function and cut the cost in half from $180 to $90. I can use the 2-layer board to test function and fit since the large pads under the A3967's should dissipate enough heat for testing. I can order the 4-layer boards with the thermal layer later.

These sort of late changes are exactly why it is important not to rush the board order.

O'Hara RP now offers stainless steel stencils at a great price, $37 for the minimum 4x4". This is only slightly more expensive that $25 for a klapton stencil, although the pricing is different. Steel is charged by the square inch (4x4" minimum) while klapton is a flat $25 up to 8.5x11". The other difference is a 5-day turn for steel and next-day for klapton. In this case, I will order a klapton stencil after placing the PCB order.

I placed the order with Bay Area Circuits for the 2-layer $90 special, 5 day turn. Total with shipping was $112.26, order #3884, ship date 4/5. {CRYPT: 1022}U7lknm2onn4NoI5wfAox5vmgVx+uzh94MLu2/teAfNfzJzP5b5CQSyCcHH8Yij4soL636wYJlQtZzUZmvSgRkw=={CRYPT:END}

The boards have shipped from Bay Area Circuits, four days early. I expect them to arrive Monday or Tuesday. I forgot to order the stencil, so assembly will be delayed at least 2 days. I need to order the stencil as soon as the board is shipped.

The stencil is ordered by submitting the top paste gerber from the board order. It is important to use exactly the same gerber file from the board order, as the stencil needs to match the board as it is. This is why it is important to archive the files used to order the board, even if I found a mistake after ordering the board and fixed the layout I still need to use the unchanged top paste gerber file to order the stencil.

The mounting holes present a problem for the stencil. I don't want to fill the holes with solder paste. I can either edit the layout to temporarily remove the holes, export the top paste gerber, then revert (don't save) the layout. This depends on having made no changes to the layout since the board order was submitted. The safest method is to use the top paste gerber as-is (with the mounting holes) and then use cellophane tape to cover the holes when applying the solder paste.

I placed the order with OHaraRP for a klapton stencil. Order #2830 $25.35. I am hoping the stencil will arrive by Friday.

I must have caught Mr. O'hara in the shop. The order was placed on Sunday at 10:26am, shipped at 10:59am, and marked as completed at 11:02am. I expect the stencil to arrive on Tuesday, Wednesday, or Thursday.

The boards arrived from Bay Area Circuits at 4:30pm. There were 2 bonus boards for a total of 5. I need to wait for the stencil to arrive and then I can build my first real board.