An Incredible Project

DARwIn-OP is a humanoid open source robot developed by some prestigious universities. It’s not just a toy, but an advanced research platform; commercial version cost USD $12,000.00.

Darwin-op

Some time ago I found a guy in my city that is building this thing on their own and I was amazed; that involves some serious metalworking, electronic and programming skills. He had some trouble because the largest part has a size larger than the cutting area of his machine (a 5400 Sherline CNC mill), so I provide my machine to do the cut; that was a lot of fun. So here is his site: http://openrobot.cl.

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Painting

So. My business began in May. The original idea was to build and sell things, but I realized that it’s better to start doing just one thing: sell things. So now I’m Sherline dealer in my country, being my focus to sell cnc solutions. Indeed, it’s not just to buy-and-sell business. I bought cnc-ready machines, add the rest and do some modifications (like to add spindle control). Also, I deviated from this and committed to build a cnc machine from scratch, for a jeweller (lesson learned: never to promise something you have never built).

Things have been hard. Accounting, buys, legal issues, design, programming…. a lot of work, and I’m just alone. I already collapsed but now I’m ok, relaxed and letting things flow. I will close my first deal next month; two machines for a university lab, and hope to repeat the process with less pain and in shorter time.

And, in the middle of all of this, I discover that I can paint, and that I need to paint. Saddly I’m doing just one paint in the month or something like this. Sanddly, because painting it’s a lot of fun… and now I think machining and all of this crap it’s so boring!. Just joking. I will always love machines…. and painting.

No one in my surroundings has been interested on this or said my paintings are beautiful, but I don’t care too much. I just love them.

Acuarela-03-Cute_Girl

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Meanwhile…

I will start a small (indeed very small) business soon; I mean, begin to create and sell some things. As I’ve said before, I used to work as software developer, and tough it’s not as bad, machines, tools, electronics and creating things is what I love and from what I wish to live. A lot of people around me are a bit sceptical (and sure they have good reasons), but I really don’t care; failing doesn’t really worry me. What worries me is to see time going without doing all can be done to achieve what I want (I know it sounds a bit cliche).

So, I’ve been doing several things in this days: setting up a FreeBSD server, switching to Ubuntu and open source tools, and starting to prototype my first product.

desktopMy Server

A version control system can be very useful to store and keep the track of changes of your work (even if you work alone). I already had a dusty FreeBSD server (I really love FreeBSD) with subversion and other things, but I wish something fresh so I install the last version (10) and setup subversion, websvn, dokuwiki and some other things. These are really nice tools.

Ubuntu and the open source

I had never been a technology enthusiast. My notebook is old, I use my old phone just for calls and up to some week ago I use windows xp on my old PC. Linux never attract me as desktop platform; I had all I need on windows. But when you wish to do some serious work, linux it’s unbeatable. Forget about viruses. Download all you need, free, from a central repository. I can easily do a new install, with all the tools I need, then checkout all my work files from my svn server and a get a working environment in a breeze.

Just one small complaint: Ubuntu’s default desktop environment it’s not resource friendly. So if you have old equipment, it will not run very smooth. Nevetheless the solution it’s very easy: install lxde, a lightweight desktop manager. I love lxde so much now. Also, maybe I give a try to lubuntu in the future.

From Eagle to KiCad

I’m a Eagle fan. But free version is for non-commercial work and has a limited footprint.  So I had two alternatives:  pay a Eagle licence (about $575) or try an open source alternative. The first time I put my hands on KiCad, some time ago, I find it a little polished and not very easy to use tool. Sure, I was a Eagle user. But when you begin to use KiCad and get used to its own way of doing things, you begin to love it. Sure, it’s not bundled with so many components as eagle, but it’s really easy to create a new device/footprint (also there’s a lot of extra libraries out there). And, although the board doesn’t update automatically when you add a new device, updating associations and netlist it’s just plain simple. My only complain: all footprints are in one big list, there’s no filter. But I can live with this. Good bless KiCad developers.

My first product

My first product will be a simple accessory for the Sherline lathe; some small parts and a bit of electronics, nothing special. My main objective it’s to get selling experience. Once I get confidence I will start sell more elaborated things (like a micro table saw kit or something else).

Name and domain

Finding a good name for your business it’s not easy, and finding an available .com domain for a good name it’s almost impossible. It wasn’t easy, but finally I did make a choice that has an available domain; now I should choose a domain registerer and webhost.  It’s sad buying and reselling domains be a common business.

Selling

I’m still not sure if I will sell on eBay or in the .com site. Actually there are a lot of alternatives to eBay, but I think eBay is a good starting point. Also, if you wish to create your own online store, there’s a plenty of free software tools. Some things I hate to deal with are legal and accounting issues, so I will tackle them later.

I don’t like to call myself an “entrepreneur” or something like that; I just want to give the effort some things deserve.

sceptical

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My first cnc part

I should say the hardest step in making this part was to press the start button (I’m a chicken).

linuxcncfirst_cnc_cut_01b first_cnc_cut_02This 1mm sheet was held to a mdf plate using Carnauba; that seems to work nicely. Badly I made a mistake and the DOC was about 0.5mm (hence two runs where required), so I’m still not sure if 7 IMP is ok for 1mm DOC.

Things I learn:

  • Finish was ok in round cuts, but not so good in slots. Next time I will separate roughing and finishing, so I can clean the chips before finishing passes. This is when hand coding gcodes pays.
  • I need to buy Acetone to clean Carnauba.
  • Regarding outside diameter, I find a max of 50.08 and a min of 49.90. May be this has to do with backlash (I have backlash compensation enabled btw).
  • TODO: a tool height setter artifact.
  • My cheap Canon photo camera sucks taking videos.

The next task will be to cut the definitive encoder wheel for the machine spindle.

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Preparing the first cnc cut

Up to this point I’ve worked in the lathe and the mill without worrying too much about speed and rpm calculation, trusting in my own experience and “feeling”, as a lot of hobbyists, I guess. Tooling wearing wasn’t ever an issue  to me; carbide tools seemed to last almost forever. Until I grasp Machinery’s Handbook and read “tool life for milling… should be approximately 45 minutes” (!!). So clearly in the cnc world choosing the right cutting parameters matters.

The cutting setup of my first cnc project involves:

  • 5052 Aluminum sheet, 1mm thick
  • 2mm, 3 flute uncoated carbide end mill
  • 1mm DOC
  • 2800 RPM
  • No coolant, just a some WD40

This LMS table states a speed of 165 FPM for 6061 aluminum (I guess it’s for HSS). So RPM = (165 x 4) / 0.0787 = 8386. Now, according to this, 0.002 IPT (inches per tooth) is suggested for 0.05 DOC, 1/8″ hss end mill over aluminum (closets size); 0.0015 IPT for my 2mm endmill seems reasonable. So using the max rpm’s (2800) gives me a feed of 2800x 0.0015 x 3 = 12.6 IPM or 320 mm/min.

Of course, due to the complex nature of this topic, suggested parameters for material/end-mill can vary a lot. American-Carbide suggest a feed of 16.000 rpm / 11.8 IPM for this cutting setup. And Whitney Tool states a cutting speed of 600 FPM for hss and 1200 FPM for carbide. As always Practical Machinist is a good source of knowledge.

Now some real world experience in the Sherline world.  This guy  broke his 2mm carbide endmill at 8 IMP, 0.5mm DOC. This other guy broke his 1/8″ 4 fl endmill  at 6000 RPM 14 IMP, 1.27mm DOC. In a test in my manual mill three turns per second (7 IPM)  doesn’t seem to break the tool.

So i think I will stick to 7 IPM for now and see what happens, and maybe later I get a set of teen end mills to do some testing and push further. Also, It’s clear I need to order the 10.000 RPM pulley set.

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