Review: Smart-Prototyping.com PCB fabrication

This was my first time ordering from Smart-Prototyping.com. I was quite impressed by the speed they produced my PCBs. I ordered 75 PCBs with the following specs:

• Max X-Dimension (cm): 15
• Max Y-Dimension (cm): 15
• Layers: 2
• PCB Thickness (mm): 1.6
• Copper Thickness: 1 oz
• Surface Finish: ENIG
• Solder Mask Color: White

I placed my order on the 23.12.2014. They shipped it on the 30.12.2014 and I got the parcel on the 5.1.2015. I paid 393USD which is about half the price I would have paid at my regular PCB house.

After the first order came out reasonably well I ordered much more complex boards to see if the quality is still ok. This time both boards had 4 layers. One board was made with 2oz copper thickness while the other had a lot of 0402 and some QFN footprints.

Packaging

The packaging of the 75 low complexity boards wasn’t the best I’ve seen so far but it was o.k. When I opened the parcel I noticed that the vacuum seals of the PCB packs were broken. This kind of defeated the purpose of putting a small pack of silica gel into the packs. Since I’m going to assemble the PCBs quickly after reception it doesn’t really matter.

The second batch which consisted of 2 different boards and stencils also came with the vacuum seals broken. Again not a big problem in my case but still.. The put the PCB’s in the frame an shipped it like in the picture below.

Overall PCB Quality

The quality of the first batch of PCBs was quite good. I’ve seen better but also worse. The edges are smooth without any fibres sticking out. The substrate is normal FR4 but some of the PCBs are slightly warped. Solderability is excellent without any dirty or damaged pads. The second batch also came out very well. This time some boards were also warped but much less than the ones of the first order. In order to check wheter they really used 35/70um copper I took a closer look with a high precision microscope.

There are some pads for QFN, TSSOP and 0402 parts. I haven’t found any errors so far, I’m impressed.

Here’s a picture of a single! QFN pad. The surface  quality is excellent (Ra. in the far in the sub micrometer area)

The thickness of the 35um copper board is actually a little bit less  than 35 um (coating included) but its not way off the nominal value.

The copper thickness of the 70um board is around 81um. Better than expected!

Silk screen and Solder mask

The alignment of the solder mask is very good but on some PCBs (first batch) it doesn’t reach to the edge of the board (as shown in the picture) it doesn’t affect the functionality but it just doesn’t look very nice. On one board there is a small place where the solder mask doesn’t stick to the PCB. The solder mask of the boards of the second batch was also excellent.

As well as the solder mask the silk screen is perfectly aligned. The silk screen is ok for the size (1.27 mm, Ratio 12%) but I wouldn’t expect the soldermask to be perfect for smaller font sizes.

The smallest silk screen font size was 0.86mm. As you can see it is still easily readable. This time I used a larger ratio (15% if I remeber correctly).

Silk screen and solder mask over a tented 0.3mm via.

The Stencil

The first unframed stencil I received had a slight bent in one place and therefore didn’t sit flat on the surface of the pcb. The stencil is still usable but I have to be careful when I dispense the solder paste. They also altered the shape of the 0805 smt components.

The framed stencils were of exceptional quality for the price. They used 0.125mm? stainless steel.

The contours are sharp and applying the paste works very well.

Conclusion

The PCBs are worth the price and I will definitely use the service again. They also sent me 80 instead of 75 PCBs (first batch) which compensates for all the tiny imperfections. The second batch of boards were high quality boards meeting the requirements and my expectations.