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hoppo
16-04-2012, 12:01 PM
Hi there, I stumbled across this site a week or two ago, as I am building a simple camera dolly and wanted to automate the linear motion. This site got me thinking how much cheaper my project would have been if I could have fabricated a few of the parts myself, rather than buying stock parts. First off I thought about buying a CNC machine, but then for the same reason I didn't buy a camera dolly, I.e. expense, I'm now looking at building one! I think I've got the CNC bug.:encouragement:
From what I can see, the main expense comes from the ballscrews, and mountings. I have a budget of around £500. Is this a realistic budget for a first CNC build or should I be looking at a cheaper or more expensive option? The problem that I have is that I would like it to be perfect! As I tend to be a little bit meticulous when it comes to these things. Or should I start with something simple using trapezoidal lead screws and use this to build up to a machine that is more sturdy and accurate? I'm thinking I should just go for the best build that I can, however the dilemma that I have is to keep the costs down it would be nice to be able to fabricate my own parts however I can't unless I have a machine!!
I'm sure many of you guys on here have been in this exact same position. What should I do?

See you all around.

Hoppo.

Lee Roberts
16-04-2012, 01:27 PM
Hi hoppo,

I too have an interest in photography; I also note the price on some of the linear dollyís available. I canít remember the one I looked at now but its main linear component is one from a company called igus.co.uk, a plate machined on a cnc machine is all they have really added to it.

Fair play to them taking a product and adding value to it!

I was thinking a ďbetterĒ version would be one that uses a lead screw and stepper hooked up to a pendant, I noticed from some of even the best YouTube videos of people using this device they still didnít have the smoothest motion that could be achieved.

This little project is on the back burner for me but I will be keeping my eye out for you and how your getting on.

Realistically you need to be looking at a budget of £1500 to start with, but again that is really pulled out of thin air because lots of other factors come into it. How big will your machine be, what materials will you use to fabricate its construction, will you be commissioning other machinistís to fabricate the parts for you and on it go's !

There is really allot to learn and understand, but donít worry! This is the place to find out just what youíre letting yourself in for. My suggestion at the moment is to continue reading the forums, you will find lots of occurrences of the same questions coming up and being answered, however there is always more to learn and what you donít find out on one thread, you will then pick up on another.

Ask as many questions as you have and when/if you get to a point where you have information overload, jump into the DIY Machine Building (http://www.mycncuk.com/forums/forumdisplay.php/31-DIY-Machine-Building) section for a little visual R&R on what can be achieved and made possible.

Good Luck & Welcome !

.Me

Lee Roberts
16-04-2012, 01:50 PM
Here is a video of the igus DryLin system i was talking about above, there is a company (or was) that sell's these units with the plate and everything ready to go.


http://youtu.be/X9dCFwYeTEc

.Me

hoppo
18-04-2012, 01:00 AM
Hi Lee,

Thanks for the reply, it's good to see that these forums are active and so supportive of newbies like myself. Yes the camera dolly that I have made/ am making, includes a stepper motor that I got off eBay, and a cheap lead screw that I've purchased from a local DIY store. I'm driving it with an Arduino board and cheap driver circuit that I found on eBay. Basically it carries an SLR camera, and I have programmed the Arduino to drive the stepper motor by turning it for x amount of revolutions. Then to pause and take a photo, and repeat until it has travelled the full length of the dolly. I then compile the photos together on my computer, and hey presto a motion timelapse movie. I prototyped the device using wood as a proof of concept, and it worked a charm. I've now started to rebuild it with a more robust frame, and recently purchased some aluminium profile, which is really nice to work with.

So onto the CNC router project that I have started for myself, I thought that I would tackle it in a similar way. So my plan is to use aluminium profile for the frame, and ballscrews or trapezoidal lead screws to drive the linear motion, with supported steel rods and linear bearings. Add some stepper motors and required drivers get some software and hopefully off I go! :tears_of_joy: I was thinking that a good size would be 1000 mm x 600 mm x 300 mm, which would adequately cover all the needs that I currently envisage that I would have for the machine. Do you think this may be a little ambitious for a first project? Additionally any views on buying parts from China? I have seen a lots of relatively cheap kit that is available on eBay that would bring my project price down considerably. Or are the parts inferior quality? Or would they be okay for a first build?

Apologies for the questions but I have a lot going on in my head and feel this is the ideal place to ask them!

Cheers,

Hoppo.

JAZZCNC
18-04-2012, 01:15 AM
So onto the CNC router project that I have started for myself, I thought that I would tackle it in a similar way. So my plan is to use aluminium profile for the frame, and ballscrews or trapezoidal lead screws to drive the linear motion, with supported steel rods and linear bearings. Add some stepper motors and required drivers get some software and hopefully off I go! :tears_of_joy: I was thinking that a good size would be 1000 mm x 600 mm x 300 mm, which would adequately cover all the needs that I currently envisage that I would have for the machine. Do you think this may be a little ambitious for a first project? Additionally any views on buying parts from China? I have seen a lots of relatively cheap kit that is available on eBay that would bring my project price down considerably. Or are the parts inferior quality? Or would they be okay for a first build?

Apologies for the questions but I have a lot going on in my head and feel this is the ideal place to ask them!

Cheers,

Hoppo.

First hello Hoppo,

Your on the right lines with using supported rails good choice.
The size is ok and not to ambitious but depending on the work involved then I'd reconsider the 300 Z axis.? It's a little on the long side for any kind of hard-ish work, 200mm is a better size and addiquite for most work.

Regards the chinese stuff then for things like like ballscrews and supported rails etc then yes they are great but be very careful regards the electronics, drives etc personally I'd buy the drives here in UK from Zapp or the likes.
Chai at linear motionbearings on ebay is the guy for all your ballscrews and rails,cable chain etc and can fully vouch for him great guy 110% trust worthy.

Tip would be don't buy the motors,drives,PSU etc untill you have at least designed and settled on the components for the frame. Don't try cutting corners with electronics it's false economy and just leads to frustrations.

Keep asking the questions and resist the urge to buy untill you fully know it's the right way to go or whats best for your intended purpose.

Good luck.

blackburn mark
04-05-2012, 11:05 AM
I'm driving it with an Arduino board and cheap driver circuit that I found on eBay. Basically it carries an SLR camera, and I have programmed the Arduino to drive the stepper motor by turning it for x amount of revolutions. Then to pause and take a photo, and repeat until it has travelled the full length of the dolly.

you shouldent really stop to take the photo or you will have no motion blur, it will show in your finished project as a perceivable jump from frame to frame on any close objects with hard edges

the begining of saving private ryan on the beach is shot at a 45 degree shutter angle to give it a stark look
the standard is usualy 180 degree shutter... 50% of the time the shutter is open and 50% of the time shut
EG: a 1 second exposure requires a 1 second delay before the next exposure... you have no need to worry about the speed of the tracking as the motion (smoothing) blur will correspond accordingly at whatever speed you choose

so as well as making your machine a tad more simple to make and use this will also make your films smother and more "filmic" between frames