New Machine Build- Machine #2 Al Frame, Belt Drive 1300*900

[rjfurness@bigpo]

Hello All,
my name is Jason Furness. This will be my second machine build. I built a Solsyvla machine under the tag line 'Solsylva in 7 Days'. Five months later I finished the machine as work rudely interrupted me on a number of occaisons and dragged me off to other parts of the planet.

I will be using an Aluminum frame and some linear rails that Ed has donated to the cause. The parts are a bit smoke damaged but can be cleaned up and the rails refurbished with new ball bushings. I owe Ed a carton or two for these parts as they have saved me a lot of time and money rather than importing them.

The frame is a 1300*900 size so I am expecting to get a 1200*800 cutting area.

My first machine used a HobbyCNC controller and 305 oz.in steppers so that I could transfer the brains of machine #1 into machine #2.

My major use for this machine is to cut parts for my R/C planes as well as to cur out dinsoaur skeletons with my son to help him make some money to pay for his guitar. He is nine so it is acoustic, not electric, at this stage anyway.

The machine will be cutting balsa and plywood up to 13mm thick, G10 composite material for control horns etc. I would like to cut aluminum also to enable me to make landing gear parts if I desire. I expect that if I can cut these materials I could also cut thinner brass plate when the urge to make some WW1 creation with lots of fiddly bits overcomes me.

Jason

[rjfurness@bigpo]

Here is the Al frame. I have cleaned things up a bit since then and it all appears true.
[IMG][/IMG]

These are the disassembled rails and support extrusions. They all appear to be fine.
[IMG][/IMG]

Here are the blocks and the ball bushings. The blocks were running very rough on the rails. It appears the heat has distorted ball bushings and bearings. They can be replaced once I figure out how to get them out of the guide blocks themselves.

[IMG][/IMG]

A set of replacement bearings and I should be away. I think I have enough rail to make up all of my axes.

Jason

[rjfurness@bigpo]

Hello All,
my plan is to buy a VFD for this machine, my question to anyone is 'What size VFD do I need?'

As I said earlier I will be cutting plywood up to 13mm (rarely) and want to cut aluminum for undercarriage parts (rarely) For these thicknesses, multiple passes are not an issue, cycle time is not important.

I am wading through the relevant threads at the moment to work it out.

Jason

[rjfurness@bigpo]

Hello All,
I plan on using belt drives to moves the axes, I haven't figured out pulley ratios yet but have found a few threads on the subject. Any advice is appreciated. This will be a TLAR design (That Looks About Right).

[rjfurness@bigpo]

The Gantry will have Aluminum side plats and use at least one Al 'C' Section for the Y-Axis. The Z-axis base is expected to be a flat plate at this stage. Once again any advice or references to relevant threads is gratefully accepted.

I want to add a dust extractions system and vacuum hold down table to the unit. The main Al frame will be mounted on a steel framed table which will also hold the MDF for a cutting base. The hold down table will be mounted to the MDF base.

There are a few really good threads about vacuum tables and numerous dust extraction ideas so I will work my way through them as it gets closer to the time. Aquarium pumps and largeish tanks appear to be a popular and cheap solution to providing colling water for the VFD.

Jason

[scotta]

Hi Jason!

I must say I was surprised to see a local on the zone. I've been lurking around the forum for a while. Before we started the business I was a strong contributor over on RCGroups and at the time Tim Smith was doing a lot of CNCing form me on his Bridgeport.

I've missed being in the shed and designing and flying so in my spare time I have been planning my own cnc and most recently purchased the plans for Joes 4X4 Hybrid. Parts for which are not quite as readily available out here.

I've found that TEA Transmissions is the cheapest for Trapazoidal threaded rod and will work with DumpsterCNC antibacklash nuts but also checkout linearmotionbearings2008 on eBay. They are selling rolled C7 grade ballscrews, couplings etc at pretty reasonable prices. I'm looking to get a package price from them for screws etc as well as a spindle for the Hybrid to compare with local supply. I will most likey use EMC2 (I like linux) and Gecko 203V's as I have a 80V supply ready an waiting for the project. Mine will be a slow and drawn out build but I look forward to watching yours

The Mechmate forum has some great threads on vacuum hold down tables and for vacuum pumps checkout http://www.centralvacuummotor.com/ they supply a lot of vac motors to the mechmate guys and hopefully will ship to Oz.

Best regards

Scott Alford
Orange

[rjfurness@bigpo]

Hi Scott,
likewise I was suprised to hear from you!

I am finishing the cleanup tomorrow and will then start working through the gantry dimensions to get the plate cut up. I can source some new ball bushings locally, at least according to the tool room guys I will be able to.

I am using the HobbyCNC gear from my first build on this machine. I will be sourcing a spindle, probably from linearmotions on Ebay.

Jason

[scotta]

I've been playing with Joe's original design to see how the linearmotionbearings ballscrews would work so that I can work out the screw lengths required to get a price. This will determine if I stick with the original threaded rod design or not. My version of the 8 bearing x axis carriage

[rjfurness@bigpo]

Hello Anyone,
I have been a bit stuck on how to proceed with this build.

I think I will have some difficulties getting dedicated Al components machined up as side frames for the gantry. I have had a long look at using 80/20 because I think it may require less machining in order to get to a usable machine.

Any opinions on this, or the relative cost?

I would prefer to not do a detail CAD drawing of components as I would need to learn CAD for real so the flexibility of designing it as I build has some appeal.

Again has anyone done this sort of 'Make it up as you go along' process and what are the pitfalls of it.

Thanks

Jason

[sonicwonder2000]

Originally Posted by rjfurness@bigpo Hello Anyone, Again has anyone done this sort of 'Make it up as you go along' process and what are the pitfalls of it. Thanks Jason

Yes, I am currently in the process of this "make-it-up-as-you-go" design and what I have been noticing is the magic number is three. Expect to redesign/build every component of your machine 3x before you are successful. Three times the duration, three times the effort, three times the cost. Sometimes you will complete one component successfully, only to discover that it needs to be changed later in order to make something else work. IMHO, it is far better to build everything in CAD before you start and then modify things in CAD as you construct. This helps avoid errors and is good training. If you're going to master CNC, mastering a CAD programs can't hurt . Also, I think the only things that absolutely need to be machined accurate are your rail supports; as long as your x,y,z rails are parallel to its pair and perpendicular to all others, you will be fine.

[rjfurness@bigpo]

Thanks for the input, I am thinking that their are probably 5 or 6 components that need to be cadded up correctly and I can muddle my way through them on the computer with a bit of time.

I am used to the concept of measure once, cut twice, and swear three times so I can relate to the 3x concept quite readily.

Jason

[rjfurness@bigpo]

An update after little work for a while. I have been privileged enough to be given a CAD design for a router that I can adapt to the frame I have.

I need to lengthen the drawings of the two components that form the carriage and can then get a kit laser cut. The people who will weld it up for me for nothing can start in January so it will be a while before I make substantial progress. In the meantime I will order my replacement linear bearings, pulleys, belts, and spindle.

Jason

www.cashfocusedcoaching.com