DC Motor Driver X6

 

This is how I got my Motor Driver PCB made By 

PCBWay is a Full feature custom PCB prototype service.

This is the file for this PCB: Tims_DC_Motor_Driver_X6_Mk2.zip

You can use it to try out PCBWay's Order form.

First it is necessary to design the circuit. This post explains how I came up with the design for the circuit.

There are many applications to chose from to design a PCB (Printed Circuit Board), I use KiCAD it is A Cross Platform and Open Source Electronics Design Automation Suite (and I support Open Source).

I am going to be very basic with the instruction to using KiCAD.

KiCAD   do a very good   Introduction to KiCad.

I recommend reading it, at least refer to it to learn more what I have shown.

So lets get the circuit drawn. Open KiCAD.

The first window that opens is the Project Manager.

On the right of the Manager are the buttons that will open the stand alone Tools for creating your PCB.
To the left is where you create and manage all your files.

This is where we start.

If you are starting KiCAD for the very first time

There are two ways to start a project. "Create New Project" and "Create New Project From Template".

The "Create New Project From Template" is something to use one you have become used to using KiCAD.

 So for now, click "Create New Project" .

This opens the standard File Dialog.

Make sure that the Checkbox in the lower left of the Dialog Window is Checked.

This will create a folder with the name you have given your project and all the files for your project will be created inside this folder.

Click save.

The Project Manager should now be populated with files like I have shown above.

The next ting to do is Create/Edit our Schematic.

 Click the "Schematic Layout Editor" icon in the right side of the Project manager.

This opens the "Schematic Layout Editor"

This is where we place all the components and connect them to each other.

 To place a component (symbol) in the editor, click the "Place Symbol" icon on the right of the editor.

The "Choose Symbol" Window will open.

If this is the first time you have chosen a command that uses the database, it may take a little time to open.

The first time you use a command that uses the database, it will load the database into memory. Depending on how big you make the database, depends on how long it takes to load.

The "Choose Symbol" Window is where you select the component you want to add to the circuit.

You can type what you are looking for in the filter textbox.

Once you have found the symbol for the component you want to add to the circuit, in the bottom right of the "Choose Symbol" Window you can also chose the type of Footprint the component has.

Once you have selected the component you want, click OK and place it in the circuit where you want.

Once you have placed all you components in the "Schematic Layout Editor"  you need to connect each of them to which ever component they connect to.

To do this, use the "Place Wire" tool. 

Now that the circuit is done, the next step is to position all the components on a board which will become our PCB (Printed Circuit Board).

But before we can use the "PCB Layout Editor" we need to create a "Net List" of all the components.

The "Net List" is similar to a bill of quantities but with extra information like which component is connected to which.

To make sure that all components have been annotated with a unique names/reference, the "Annotate Schematic symbols" tool can be used.

 Clicking the  "Annotate Schematic symbols" tool button brings up a window where you can select options on how the schematic is Annotated.

Just click "Annotate" button, then the "Close" button.

With all the components annotated a Net List can be made.

 This is just simply a matter of clicking the "Generate Netlist" button.

An Options window will open first, click the "Generate Netlist" button.

A file dialog window will open to select a name for the Net List and where to save it.

I just use the default it provides. Click the "Save" button.

The Options window will close automatically when the file is saved.

If the annotation of the schematic symbols had not been done, you would be prompted to do so before creating the Net List.

Now that the Net List has been created, it's time to create the PCB.

Click the "PCB Layout Editor" icon in the right side of the Project manager.

This opens the "PCB Layout Editor"

As I have mentioned I am being very basic with the instruction to using KiCAD.

I will be mentioning the basics and what I think is an important part for getting the board made by PCBWay.

When the "PCB Layout Editor" first opens, it will not be populated like the image above, it will be empty.

The first thing to do it import all the components from the Net List.

Click the "Load Netlist" button at the top of the "PCB Layout Editor".

This will bring up the "Netlist" window.

The first time the "Netlist" window is opened, you will have to browse the the netlist file.

Do this by clicking the folder icon in the top left corner. this will bring up the standard file dialog window, chose the Netlist file created earlier and click "open" button.

The "Netlist" window will load the Netlist file and list the changes that will be applied.

Click the "Update PCB" button.

When you click the "Update PCB" button in the "Netlist" window, you will find that all the components are attached to the mouse cursor.

Just place you mouse in a location on the page and click the left mouse button.

Click a blank area of the page to deselect all the components.

You can now move and place each components on the page to where you want them placed on the board.

To create a board, you use the "Edge.Cuts" layer, drawn with "Add Graphic Lines" tool.

Select Edge.Cuts layer by using the dropdown list at the top of "PCB Layout Editor" or by clicking the Edge.Cuts layer in the "Layers Manager" on the right.

 Use the "Add Graphic Lines" tool to draw the shape of you board.

The other "Add Graphic ...." tools can be used to draw more complex shapes.

The "Add Graphic Circle" tool is used to insert holes.

The shape and size of the board is all done on the "Edge.Cuts" layer, make sure there are no brakes in the drawing of the shapes.

 Use the "Rout Tracks" to place the copper traces onto the board.

This can only be done on the Copper layers.
F.Cu Layer is the Front Copper Layer.
B.Cu Layer is the Back Copper Layer.
Select the copper layer as you did for the Edge.Cuts.

 You can add a Via using the "Add Vias" tool if you need to change the side that the copper track runs.

 After placing all your components and joining them all with copper tracks you may want to write some text on the board.

 You can do this using the "Add Text on Copper Layers or Graphic Text"

This can be done on layers:
F.Cu - Front Copper Layer. Text is written with the copper on the board.
B.Cu - Back Copper Layer. Text is written with the copper on the board.
F.SilkS - Front Silk Layer. Text is written in ink over all coatings on the board.
B.SilkS - Back Silk Layer. Text is written in ink over all coatings on the board.

Remember when looking at text on the back of the board in  the "PCB Layout Editor", it will look mirrored (reversed), as the default view of the board is viewed from the front.

One important thing to do when creating you board is to set the "Origin" from which all dimensions and placement are made. Most manufacturers preferer this to be set to the bottom left of your project.

To "Place the Auxiliary Axis Origin for some Plot File Formats and for Drill and Place Files".
Simply click this button and click where you want it to be.
Don't confuse it with the Add Layer Alignment Target.

Now that all is done, it's nice to have a look to see what it looks like.

In the top left of the "PCB Layout Editor" click on View, then choose "3D Viewer"

This will open the "3D Viewer".

In the "3D Viewer" you can rotate zoom in/out and render the PCB.

The model used by the 3D viewer can also be ported to FreeCad, to be added to any 3D model you are making.

To get this made by PCBWay, the next step is to create some plot files they can use.

This is the easy part, it's just a matter of setting the right settings and creating the files.

Click the "Plot (HPGL, PostScript, or GERBER format)" button in the top left of the "PCB Layout Editor".

This will open the "Plot" window.

First thing is to create or set the output directory. Normally this is called "Plot_Files".

Click the folder icon in the top right of the "Plot" window. This will open a standard folder dialog window. Select/Create the folder to place the files in and click "Select Folder".

In the top left you will see that the Plot Format is Gerber. This is the type we want.

What you see above should be default. With one exception.

Also in general options you will see that "Use auxiliary axis as origin" is checked. This is required.

Once you have all checked as shown above.

Click the "Plot" button. This will create the Gerber files for all the layers we need.

There is a PCBWay Checklist if you would like to check.

Next is needed the drill file to drill the holes.

Click the "Generate Drill Files" button. The "Generate Drill Files" window will open.

The destination folder should be the same as set in the "Plot" dialog window.

Make sure the selections are as above. Especially the "Drill Origin" is set to Auxiliary Axis.

Click the "Generate Drill File" button. This will create the Drill File.

Close the "Generate Drill Files" window.

Close the "Plot" window.

In the Project Manager there is a button to open your project folder, click it.

Open you plot folder.

Select all the files and create a ZIP File of them.

Name the ZIP File with the same name as your project. This is the file we will use to order the BCB's from PCBWay.

Time to place an order with 

Go to there web site.

The top part of there home page should look like this:

As we are creating our PCB's from Gerber files.

We can go straight to the "PCB Instant Quote"

This will take us to this page.

It looks like a lot to fill in but the Gerber file we have created will do most of the work for us.
So the first thing to do is select this option.

This alters the top of the page slightly.

We now have an option to upload Gerber Files.

Click the button to "+Add Gerber File"

This will open the standard File Dialog Window.

Brows to the ZIP File created in our project.

Select the file and open.

The top section of the page changes again.

It states if the upload of the Gerber files where a success.

It also shows you the front and back of your PCB.

In the top right of the form, you will see a link to a Gerber Viewer.

This will open in a new page and you will need to upload the ZIP File again.

With the Gerber viewer you can check all the layers that make up the PCB.

If you are assembling the SMD (Surface Mounted Devices) on your PCB your self, then there is a tool you need.

You will find it very difficult to mount your components without it, I cannot emphasise it enough.

Unless you have a laser cutter to make your own, then you need to purchase an "SMD Stencil".

If all your components are TH (Through Hole) components, it's not required.

I will be showing what a Stencil is used for later.

So if you look at the bottom of the form, you will see a checkbox for an "SMD Stencil"

Check this box.

The bottom of the form will change to show details of what type of stencil you want.

All that is left, is to create an account if you don't have one.

Select what postage you want.

And pay.

I had no issues using China Post.

Took a little time to arrive, no longer than buying items from eBay.

If you are signing up for the first time, you should also check if you have received any discount vouchers for first time customer.

Received

Good Packing.

Vacuumed Sealed.

Top                                                                               Bottom

Darkness of solder tabs is due to bad lighting, the quality is exhalent, just as I wanted.

Assembly

The first thing to do is fit the SMD's to the board.

SMD's are not soldered to a PCB in the normal way you solder TH (Through Hole) components to a circuit board.

A  soldering iron and a real of fluxed solder is not the best option.

You could try if you want, but there is an easier way.

Commercially SMD's are set in place using solder paste and placed in an oven.

When the solder paste melts (at a lower temperature than normal solder) the flux cleans the components, the solder pools and capillary action happens which pulls the component into place and hold it there until the solder cools and sets.

As I am just a hobbyist and this is my first time with SMD's on a commercial board, I don't have PCB oven, so I will be using a heat gun, not one of those for stripping paint, a small pen like tool.
This is what I have:

It's a butane torch that has several tip attachments. The tip fitted is designed to just blow hot air.

There is some degree of adjustment, using this, it's best to have it at low setting, the force of the the air blown out of the end is proportional to the heat of the flame.

If it is set to high, the force of the air blown out of the end will blow your components off the board.

It needs to be held at a distance where the force of the air is weak, but it gives lots of heat over quit a large area around your components.

As I have mentioned, solder paste is used to attach the SMD's to the board.

I just got a small 35g tub. The type I got has 183ºC on it so I guess that's the melting temperature.

Type: XG50

Alloy: Sn63Pb37

Microns; 3#

Flux: IPX3

I think there is other stuff in it, to make it workable. The container comes sealed when you get it.

I have noticed it tends to get a dry feel to it if left in the open air for a time, so I would keep the lid on the container when not in use.

Another important tool you need is a good pair of Anti-Magnetic Tweezers.

I  have also mentioned a SMD Stencil.

I have a small laser plotter I made and am able to make my own.

An SMD Stencil enables you to apply the right amount of Solder Paste to you PCB.

You use it the same way silk screen process works.

I used a piece of clear plastic I am able to cut it with my 2W laser when I make the surface dark using a White Board Marker.

White Board Markers have an ink that wipes away with a soft cloth or tissue.

Once cut a jig needs to be made so that you can line up you PCB with the Stencil.

Make sure the SMD-Stencil will not move position when placed over the PCB.

The tape holding the SMD-Stencil acts like a hinge.

As the components are very small.

I use an old pill tray to have all the components sorted.

I also printed a guide for placing the components.

Time to add the Solder Paste.

Spread the Solder Paste so that all the holes in the SMD-Stencil are filled flush.

The area in the picture on the right is correct.

This gives the correct amount of Solder for each connection.

You can see this result more clearly when the SMD-Stencil is lifted.

Next step is to add the SMD's (Components)

I hold the PCB in a grip to hold the PCB level, also I want access later to heat the underside.

Also being old my eyesight is not as good as it was so I use a magnifier with light.

Once all the components are in place, heat the area around each component with the hot air torch until the Solder Paste pools to a shiny metallic bead.

When this happens the SMD should float slightly and align itself with the pool of solder.

When this happens move to the next component.

Some times before you stat with the components it is best to heat the PCB from underneath.

Making the PCB hot before heating the components, prevent to much heat being applied to the component.

The last thing you want to do is melt the component.

Here is a video of how I solder the SMD's

After all SMD's are soldered to the PCB, next are the TH (Trough Hole) components.

These are soldered in the normal way with a soldering iron and flux solder.

And Here It Is Fitted.

I have shared the PCB Project at PCBWay here: Tim's DC Motor Driver X6 Mk2