01 October 2011

Step by step guide to the SumPod RAMPS v1.3 board

Welcome back, and as promised here are the pics of the RAMPS PCB populating (soldering on the components) process.  I work a lot with PCBs, but appreciate that not everyone has the same level of experience,  so I've taken pictures at every stage to help and guide.  I referred to the RAMPS v1.3 build from the RepRap wiki for guidance, but offer a different order that I think makes the board easier to populate.

First get comfortable and prepare your working area.

Start with the lowest profile components and build up.  First are the resistors, there are three values and the resistors of each value are taped together.  First solder in place the single resistor and your board will look like this.

Then the three resistors taped together.

And now the five resistors.  However before soldering these be aware that some of the connections will be more difficult to make than others, this is because of the board design and lack of thermal relief on some of the pads.  Depending upon the power of your soldering iron (cleanliness of board, component leg and type of solder used) you may have difficulty soldering three of the connections, indicated by the red arrows below.  

In practice this means holding the soldering iron on the joint much longer until the solder flows around and into the joint - the opposite of what you really want to do which is heat the component leg for as little time as possible.

A thermal relief is a means of keeping a good electrical connection while minimising the heatsinking effects of the copper pour, which will naturally suck heat away from the joint.  Your effectively heating the board and not just the joint.  The blue arrow points to a hole without a thermal relief and will take longer to solder than the hole indicated by the green arrow that has a thermal relief.  Be aware for other solder joints without thermal relief later in the build.

Anyway after soldering the five resistors your board will look like this:

Now the diodes, make sure to orientate them as per the PCB overlay.  In this picture I have only solderedone diode, D2.  D1 is used for supplying power to the Arduino MEGA board for operation without a PC, for example when printing from a SD card (so later I soldered this in place). 

The LED, top left.  The long leg is positive.

Small blue 100nF capacitor.  The capacitor will not fit because of the bent legs.  You will either need to bend them in to match the pcb footprint or pull the capacitor legs through with pliers, your choice. 

Next the header pins.  On the top right, I suggest you break off and solder three lots of six rather than six lots of three.  Holding the headers in place is reasonably easy for this first cluster.  For further header pins, I suggest you either tape or use a small dot of glue to hold the headers in place for soldering, since the pins are much smaller than the holes and easily fall out (frustratingly). 


Now the header sockets.  When you cut the strips do not try to cut between two sockets, it risks ruining both.  A better approach is to sacrifice a socket for each cut and clean it up post-chop with cutters or a blade.  You may also find some of the pin headers require trimming as component placement is cramped in some places.  I recommend orientating the strips with the clean end near to the big capacitor for easy fitting of the cap.

Now the electrolytic can capacitors, make sure you get the polarity right.  The PCB shows the positive hole and the capacitors have the negative leg marked.

Next add the connectors D8-D10 on the left hand side.  Slot them together before trying to put them onto the board.  Unlike me who stupidly forgot they are shorter than the MOSFETs, hence the picture.

Now add the MOSFETs.  The PCB shows the correct orientation, or just copy the picture.
 

The next tallest components are the large green connectors.  Since these connectors are much taller than the previous components, I find it easier to prop up the board to ensure they are soldered flush to the board.


Now the two poly fuses.  These hold in their holes reasonably well.

Now this is where I deviate slightly from the supplied kit and use stackable headers rather than the supplied pin headers to connector to the Atmel MEGA board.  I intend to use a SD card to print from ultimately and it's easier to do this now than replace the headers at a later date.
Finished Board

This is how your board should look from underneath.

If you're interested samples of the stackable headers can be obtained, free of charge from Samtec.  Delivery is very quick.  I used the following parts:
1x6 qty 1  SSQ-106-24-F-S
1x8 qty 5  SSQ-108-24-F-S
2x18 qty 1  SSQ-118-24-F-D

Et volia your finished board.  Already for buzzing out for shorts etc.  Enjoy.

I haven't provided details of the stepper driver boards, because I haven't received them yet.  They will however I am assured be in the SumPod kits you receive.

Until next time (only a little later) I'll post more pictures of the SumPod box and MDF components.
SumPod Guinea Pig signing off.

PS.  Check the follow up post for parts I've missed in this howto, specifically the stepper driver headers and lcd header.

6 comments:

  1. Thanks for the stackable header tip especially the where to get samples part. Will try that as I have quite a few hacks in mind that may benefit from that.

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  2. Indeed, I have just submitted the form to get some stackable headers myself. Thanks for the great write-up!

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  3. hi, fixer. did you manage to get that stepper driver?

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  4. I collected the stepper drivers from Richard and soldered them up last night. I have been trouble shooting the DIY kits for the SumPod and will amend this build in the next few days.

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  5. HI,

    Did the kit include a extruder or a rotary tool ?

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  6. The kit includes a hot end, but no rotary tool.

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