Virk I – Afterwards

By the end of the year the first unit of Virk I was fully finished, while the other eight units were under construction.

Design, build and make Virk alive was a big venture, a path full of challenges, mistakes and achievements. It was a lot harder than it seemed. Now I have a much more clear view on why 3D printing has revolutionized prototyping; nonetheless I don’t regret the path; I love wood and cnc milling.

I came to the conclusion that Virk I design is clean and solid (for what Virk I is intended), but it’s hard to make; tight tolerances everywhere. If you wish to make just a functional a robot arm… I will recommend you to stick to some open hardware 3D printable design. Unless, of course, you are a bit nuts, you love details and really want a wooden robot arm.

So what’s next?

  • Put some units for sale (check HERE). Maybe I will start a Kickstarter campaign to try to sell them and start Virk II, who knows.
  • Publish Virk I drawings. I need to make them clean and understandable, and that will take some time. I will send current messy drafts by request.
  • Vartra:

So what is Vartra? It’s another crazy wood project I’ve been working on since last month. News about that soon on insta.

 

Wood clamping

I’ve been making a lot of wood parts lately. Here, I show the three main ways I use to clamp the wood.

Long stick on vise

This is easy.

Pros: Low setup time, great for series.

Cons: Final cut-off should be carefully planned.

Disposable wood support

This is my favorite. You  just glue a piece of “decently” squared wood to the base of your blank, and use it to clamp to the vise. After machining the top and the sides, you cut away the base block and machine the underneath.

Pros: “Indexable”: you can use a vise stop so you can put your part on exactly the same position several times. So, if you have a lot of parts, you can make a round, use one tool on every part, and do another round with another tool. Of course this only have sense if you don’t have an automatic toolchanger.

Cons: Setup time: you need to cut a piece of wood squared enough, and glue to your wood. Also, if you make “rounds”, re-clamping can time consuming and, depending on your setup, prone to positioning errors.

Base block and screws

Here you machine a piece of wood and use some screws from below to secure the part. The block itself should be bolted to the tooling plate (or held on the vise). If your part has some straight holes you can look for a wood screw that thread on that hole without damaging it. I use this method for a second step on some parts clamped on previous ways (you can see the remaining of the disposable block on the back of the picture). This is the method I’ve used on my last video.

Pros: You can get a very precise positioning with the proper setup (e.g. using index pins). You can also clamp several parts at time.

Cons: Making the base block can be time-consuming. Also, you need holes where you screw can attach to, or you would need to make some holes on your part if you don’t have enough or appropriate ones.

As a final note: wood is a nice stuff to work with, but you should be careful and plan ahead your cuts to avoid tear out.

Automatic

It’s been about a year since I move all my stuff to a new location. I’ve been doing, silently, a lot of things: machine tunning, fixtures, furnishing, prototype design, components procurement, coding, etc. And I’ve been working hard on my latest project in the past months (there will be another post about that).

I’m not good at social media; I’ve been publishing just some instagram pics from time to time last year. But it’s time to start to publish content again, and i3micro.org will change to automaticartisan.com from now.

So what we have here is the final step in making a PVC, 70 tooth HTD3M pulley. Grooves where made using the Sherline rotary table and a custom tool bit, in a the same way as on my old “making gears” post.

3040 Frame

I’ve got this chinese 3040 CNC frame some time ago from  RATTM MOTOR CNC on aliexpress, for just US $ 536.07, shipping included. This is not a ready-to-use machine; you should put your own chains, steppers, stepper mounts, controller, etc.

IMG_2350IMG_2351IMG_2359This frame looks pretty good to me; It comes almost fully assembled and every axis has a pretty good sliding action. Of course you should clean the whole thing and re-grease linear bearings and ballscrews before use. Please note I did choose the version with detachable spindle bracket, so I can install whatever spindle I wish.

I’ve just finished installing wire chains, steppers and tested the whole thing. Next step would be to make an adapter to mount my 12.000rpm DC spindle.

 

 

 

 

Proof-of-concept prototype

I’ve been lazy. This thing has been gathering dust on my desk for several weeks. Desgined to be cheap, lightweight and cute. Powered by Arduino and GRBL.

IMG_2298Will this cut anything? or would be just a piece of modern art? Of couse, if this doesn’t work, I would say it was just a learning exercise, and use it as a paperweight.

Don’t ask for plans, this isn’t the diy cnc machine you wish to build. And I know, I need a better spindle.

CNC Lathe making chips and choosing a video editor

I guess I should have chosen a curvy part instead of this boring one… maybe the next time.

Now some words about my search for a decent linux video editor. I did my previous video using OpenShot; It was a bit crashy and I really don’t like the way it handles titles. So after checking some reviews and doing some tests, I finally settle on Kdenlive, which is really nice.

Power Supplies

Are you searching for a new, cheap power supply for your CNC project? Well, here you have two options for a 24V / 8A supply.

supply-comp_2I bought Sonyang for $35 just here. I don’t remember how much I paid for the MW one, but for sure it was in the same range. So here are the guts, Sonyang on top, MW below.

supply-comp_1

Some things to point out:

  • Yellow plastic cover on MW is not well designed: can’t be fully opened (I will just remove it).
  • Soldered fuse on MW, socket fuse on Sonyang.
  • Dual output 24V terminal on MW; triple on Sonyang.
  • Way better output rectifier heatsink on Sonyang.
  • Overall larger components on Sonyang.

Of course a visual inspection of the boards doesn’t tell the full history, but to me, there’s a obvious choice.

Update: Second power supply brand is “Meang Wel”, not “Mean Well” as I thought. Real Mean Well power supplies seems to be a lot better.

 

Nema23 mounts

I’ve got these motor mounts from rattmmotor88 ebay seller for just $15.67 each one, shipping and hex screws included. Shipping was really fast (fedex), just eight days (I use to wait 30 to 50 days for items from china).

IMG_2908

Packaging could be better; there are some scratches, but nothing you can’t fix with a file. Internal milling is great. External sanding finishing looks nice, but flatness is somewhat compromised; milling finishing for mounting surfaces would have been great. I don’t understand why they make motor recess 42mm diameter when it should be 38mm; anyway this is not a serious issue. Of course a critical parameter in these mounts is the space they add between motor and mount surface; 40mm in this case.

As this kind of mount allows a lot of play between leadscrew axis and motor axis, you should be careful every time you install X or Y motors, especially if you’ve got heavy motors and/or your couplings are “flexible type”.

CNC6040Z

Cheap chinese routers: will be worth? That’s the question (or was, for me). So here’s my new machine; well, just a frame. US $1040, shipping included. Here’s the link.

IMG_2862 IMG_2868 IMG_2872 IMG_2874 IMG_2875 IMG_2876 IMG_2877 IMG_2878 IMG_2879 IMG_2881 IMG_2882 IMG_2883 IMG_2887

I’d rather choose this machine instead the most popular chinese router (I have my reasons). You can search the complete machine by googling “CNC6040Z-D300 router”.

This was my first aliexpress experience. Seller was kindly, shipping really was fast, packaging could be better but was ok. No instructions, of course.

So here’s my first impression: solid parts, clean design, rough finishing. There are some  ugly faces on these parts, and sometimes it feels like you should really cross your fingers before attempting to assembly this thing. But of course, for this low price you CAN’T expect neat finishing, and most of this is just aesthetics, so it’s ok.

More info soon!