Introduction: DIY PCB Milling Machine - Part 1 - Building Frame

Hi Everyone. Welcome to Media Milan with me JCRP.

A maker space is never complete without any fast method to prototype a Electronics project. And the longest process in it is to make the PCBs. Till now I have been using the Toner transfer method and Ferric Chloride. You can watch a video I made here. Etching method involves many steps. The printing, transfer, corrections after transfer, etching, scrubbing and then drilling holes before I get so solder.

Now you can understand why I desperately want a PCB milling machine. After I design a PCB on the computer I just want to click a button and the PCB should be ready. A PCB milling machines costs about 35000 indian rupees. But whats the fun if we can't make our own.

In this part I will show you how I built the frame.

Step 1: Disclaimer:

I am not trying to cut cost. I am planning to gain some practical knowledge and share the same with you all. This is going to be a beginner series where I explain many parts in detail. So if you are a pro some parts of the video may be already familiar to you.

Step 2: The Aluminium Extrusion and Fasteners.

I am using this 30*30 aluminium extrusion. This is a T-Slot type with a small ridge. Unfortunately in Pune I haven't come across a dealer who sells v-slot aluminium extrusions. The difference between a t-slot and v-slot is this shape. V-Slot helps the rollers run on them. But for our need a common T-Slot is enough. The is a T-Nut which slides on the rail and an allen key nut screws in from the top. This is how we will be fastening most of our frame.

You can buy this T-Slot nut from the same dealer who sells the aluminium extrusions. But buy the allen key screw from any hardware store. It will be cheap if you buy from there. To cut the aluminium extrusion I used this Aluminium cutting blade on my miter saw. It gives a clean cut a perfect 90 degree which is important. So that when I stack them I can be sure its perpendicular. If you don't have a miter saw you can ask the dealer to cut them for you.

Step 3: Assembling the Frame

Here are all the pieces that are cut to length. Two short piece, two long piece and this frame. I have already built the X-Axis but we will talk about it a bit later. I am using this Allen key wrench made by TVS. They are supposed to be the best.

The base is built with these four pieces. The long pieces form the sides and the short piece goes in between them.

This is a corner block. As the name implies it fits on the corner joining both the pieces. To fasten it I will drop the Allen screw and attach it to the t-nut. This will be held loosely so that I can slide it in the t-slot. The other piece also slides in from the other side. All the while I make sure it sits flush to the ends of other piece. Then I can tighten the allen screw. Here are the both halfs ready. I have kept each side open so that I drop in some allen screws. Let me explain. There will be smooth rods here and a motor on the inner side. So if I don't drop in the screws now then later I have to disassemble and put it all back together. So do not miss this step.

So 4 screws on each side and two on the inside. If you dont understand thats fine. You will see later.

Now I close both the halfs with some more corner blocks. A last check to see if we have the number of screws right. All the while I also made sure that all the sides are flush to each other. This ensures a perfect 90 degree Y-Axis.

Step 4: Making the X-Axis Frame

Now for the X-Axis Frame. I have basically made the same kind of connection using corner blocks. These two pieces of extrusion in between provide the lateral support required. To make the fitting easy I have made sure the corner blocks are flush to the top. In fact all the corner blocks touch each other. This way I can be sure that the two rails in between run parallel to each other.

Once I loosen the t-nuts at the base of the X-Axis frame I can slide in into the Y-Axis frame. Again here I make sure that this corner block is flush to the base. So basically wherever necessary I used the corner blocks as the measuring tool to make sure each side is at the same distance to each other.

So here is the frame. It is light that it can picked with one hand but very rigid.

Step 5: Conclusion

That's it for this video. In the next video we will see how I can fit the smooth rods. I am planning on 3D printing some holders to hold them. I will also print linear sliding blocks to slide on the smooth rods. I appreciate watching this video and be sure to Subscribe if you don't want to miss the next episode. Also like and share this video if you enjoyed watching it. Sharing the video helps me a lot. Follow me on instagram @mrjcrp to see what I am working on right now.

YouTube Channel: Media Milan

Until next time. Happy Learning.

Comments

author
deepak258 made it!(author)2017-06-24

what is the length and breadth of X and Y frames??

author
pfred2 made it!(author)2017-05-06

Lowest cost was a goal with the CNC engraver I made. So I used plain construction lumber for the frame. It is not the best, but it is capable of isolation routing PCBs. I still drill the boards I make out by hand though. Because I want the through holes the right size for the leads. I use parts with lots of different size leads too. Changing bits that much on my CNC would just take me too long to do compared to drilling it on my mini drill press.

I will say this about making a CNC machine. If you want it accurate then you have to build it accurately. I used gage blocks when I built my CNC so I could get it pretty precise. It is within about the width of a piece of a piece of paper in all dimensions, or better. If you're not using mapping software when you route a board you need it that close. Or your channels won't be even.

Here's the last board I routed

LM317_Board-B.jpg