SMD Soldering Test

Tell us about your projects. Update us regularly.
Post Reply
parkview
Guru Maker
Posts: 603
Joined: Tue Jun 24, 2014 8:25 pm
Location: Busselton
Contact:

SMD Soldering Test

Post by parkview » Mon Jun 25, 2018 9:07 pm

So, being winter with a bit of spare time up my sleeve, I quickly draw up a simple PCB that incorporates some resistors and LEDs of various sizes: 1206, 0805, 0603, 0402 and 0201. I couldn't easily find any 0201 LEDs on Aliexpress, so I reuse a 0402 LED. With a momentary button and a battery this all fits onto a 28mm round PCB. I have just sent it off to Seeed for manufacture at a cost of A$25.49 (90+ boards), so it should be back in 18-24 days time.

R5 will be the challenge part.

A picture tells a thousand words, so...

Front - the fun part:
smd_test_front.sml.jpg
smd_test_front.sml.jpg (78.52 KiB) Viewed 10981 times


The back:
smd_test_back.sml.jpg
smd_test_back.sml.jpg (54.92 KiB) Viewed 10982 times

parkview
Guru Maker
Posts: 603
Joined: Tue Jun 24, 2014 8:25 pm
Location: Busselton
Contact:

Re: SMD Soldering Test

Post by parkview » Tue Jun 26, 2018 8:01 pm

As you can see this is a very simple PCB. Just for fun I had KiCAD produce a 3D view of the PCB:
SMD Soldering Test PCB.3D.sml.jpg
SMD Soldering Test PCB.3D.sml.jpg (30.46 KiB) Viewed 10976 times


And here is the circuit diagram:
SMD_Soldering_Test_V1.0_Circuit-Diagram.jpg
SMD_Soldering_Test_V1.0_Circuit-Diagram.jpg (70.7 KiB) Viewed 10976 times


As a test, I have tried to track the Build of Materials (BOM) and costs etc. As of today it's running at $1.69, however, that doesn't include a 40cm length of 0.3mm solder or packaging, so hopefully I can keep the BOM under A$2.00. Of course, this doesn't include any labour costs as this is just a hobby thing.

For those that are interested, attached below is a zip file containing all the projects files, ie: KiCAD 4.0.7 files, images and spreadsheet etc. These might will need upgrading to be used on the soon-to-be-released version 5.
Attachments
SMD-Soldering_Test_PCB_Ver1.0.zip
(261.54 KiB) Downloaded 555 times

User avatar
Jubbp
Master Maker
Posts: 209
Joined: Sun Jun 22, 2014 8:15 pm
Location: Bunbury WA
Contact:

Re: SMD Soldering Test

Post by Jubbp » Fri Jul 06, 2018 4:47 pm

Noice!!

parkview
Guru Maker
Posts: 603
Joined: Tue Jun 24, 2014 8:25 pm
Location: Busselton
Contact:

Re: SMD Soldering Test

Post by parkview » Fri Jul 27, 2018 10:03 pm

I had the PCB's produced by Seeed Fusion PCB service. They arrived back this week:

Front Panel:
Seeed_SMD_Soldering_Test_PCBs.panel.jpg
Seeed_SMD_Soldering_Test_PCBs.panel.jpg (89.97 KiB) Viewed 10971 times


Front close-up - note there is no solder mask between the 0201 resistor pads :o This will make soldering it just that little bit more difficult. Some of the black silkscreen is out of alignment too, compared with what was ordered - see the green screenshots above:
Seeed_SMD_Soldering_Test_PCBs.closup.jpg
Seeed_SMD_Soldering_Test_PCBs.closup.jpg (49.03 KiB) Viewed 10971 times


Battery Backside:
Seeed_SMD_Soldering_Test_PCBs.closup.battery.jpg
Seeed_SMD_Soldering_Test_PCBs.closup.battery.jpg (41.83 KiB) Viewed 10971 times


Anyway, I think it looks ok enough for the cost price of 28cents each. I think enough of the BOM parts have arrived for me to have a go at hand soldering up a PCB board tomorrow.

parkview
Guru Maker
Posts: 603
Joined: Tue Jun 24, 2014 8:25 pm
Location: Busselton
Contact:

Re: SMD Soldering Test

Post by parkview » Sat Jul 28, 2018 11:33 am

After a good nights sleep, I had a go at hand soldering up the board. As it's a pretty small PCB (a bit smaller than a 20c coin), I first soldered a small pad of solder onto each pad, then placed and held the component in place with a set of fine tweezers and tacked down one end. Then properly soldering down the other end, before repeating the first end. This worked ok for the larger (1206, 0805) items, but not that well for the smaller ones. The 0201 was just hit and miss, but I got it after a few goes. I did melt the first 0402 red diode, so you can see a blemish just to the lower right of it as I haven't cleaned up the flux yet.

Completed Board.2.jpg
Completed Board.2.jpg (42.31 KiB) Viewed 10969 times


The 0805 Blue LED is a bit faint, so it will need a lower value resistor.

To complete the board people will need a fine set of tweezers, a loupe (or some sort of magnification) to check the board and a multimeter is handy to test the correct diode orientation.

This has been a fun mini-project.

User avatar
seaton
Master Maker
Posts: 222
Joined: Tue Jun 24, 2014 11:41 am
Location: Bunbury, WA
Contact:

Re: SMD Soldering Test

Post by seaton » Sat Jul 28, 2018 12:28 pm

well done Paul !

User avatar
Jubbp
Master Maker
Posts: 209
Joined: Sun Jun 22, 2014 8:15 pm
Location: Bunbury WA
Contact:

Re: SMD Soldering Test

Post by Jubbp » Sun Jul 29, 2018 9:30 am

Morning Paul,

Just a reply to test the email settings..

parkview
Guru Maker
Posts: 603
Joined: Tue Jun 24, 2014 8:25 pm
Location: Busselton
Contact:

Re: SMD Soldering Test

Post by parkview » Sun Jul 29, 2018 11:03 am

I love the visual display of data and graphs etc, so below is a pie chart of the make up of the project costs. It includes a plastic bag and 30cm of 0.3mm thick solder, but not the CR2025 battery (included at a $0.0 cost), as it's difficult to travel with these kinds of batteries in some countries.

Project Costs.jpg
Project Costs.jpg (13.76 KiB) Viewed 10965 times


The top two costs are the battery holder at 30.3cents each, and the PCB at 28.3 cents each. With a bit of further hunting, I bet I could reduce some of the component costs quite a bit, but at the moment, I am only buys in quantities of 100.

parkview
Guru Maker
Posts: 603
Joined: Tue Jun 24, 2014 8:25 pm
Location: Busselton
Contact:

Re: SMD Soldering Test

Post by parkview » Wed Mar 06, 2019 6:02 pm

This project should really be called a SMD Soldering Challenge. I recently took a few kits along with me to China and a few people successfully gave it a go. Since then I have experimented with some packaging. The first type had the components glued down. It looks the best, but the glue will leek into some of the LED components and make it difficult to get them out. It also took a long time to glue each of the 20 resistor and LED strips into place.

Someone suggested I give double sided take a go. That technique halved the packaging time, but the tape doesn't hold the components down as strong as the PVA glue does. While the kits BOM cost is quite low, the labour costs are very high and most probably not economically fully recoverable in this format.

I now have 60 odd packets made up for sale at the March 2019 FOSS Asia conference, so it will be interesting to see how well they travel.

Sample Kit - glued (front/back):
SMDSolderChallangeKit.jpg
SMDSolderChallangeKit.jpg (184.78 KiB) Viewed 10534 times

Post Reply