Thread: help with a 4' by 9' cnc build
Starting on a new project for a 4' x 9' cnc machine. Before i buy all the parts i would like to ask what is the best motor size to go for on this size project?? Also can anyone recommend a nema 23 or any other kit which will include all the electronics which i need?? I have seen some ranging from 22, to 40kg but i do not understand what this means. Thanks in advance
Welcome. 4' x 9' is a monster machine and one you can spend a lot of money getting nowhere on. Start by deciding and designing the basic structure, dont worry about motor or electronics at this stage. No one can really recommend a motor or drive electronics without knowing a lot more about the machine and its purpose, all they can do is give you their own experiences.
The key issues you will need to deal with are what sort of things you will be making with a machine this size. You have some major tradeoffs betwen speed and cost here. If most of your work could be done on a 4' x 4' or 4' x 6' machine you need to carefully consider the reasons for going to 9'. Similarly are you thinking of production runs or one-offs? Is time to complete (and therefore speed of operation) a critical factor? What sort of accuracies are you looking for and what sort of materials will you be cutting?
All of these factors will influence the overall design, what drive mechanisms (screw, belt, chain, rack, etc.) would be possible and what construction techniques can be used.
Get some ideas together, sketch some drawings, post them here and get feedback.
What i am looking for is a variation of sign manufacturing and cotinuous production of items. from very large to small. I am looking for reasonable cost but at the same time something which is fast as what i can get. I have done some research and would like to follow the plans off www.buildyourcnc.com. I have the actual make covered more or less and just need help with the electronics.
thanks a million
Only problem i have is he is making a 2 x 4 foot machine while i want to make almost twice that size. what is going to be the best with regard to electronics for my machine or is there a chart or someone who has made a similar size??
Soyeb, you know what you need ?
You need a [ame="http://www.mycncuk.com/forums/showthread.php?t=1524"]What size stepper motor do I need...?[/ame] tutorial !
BlackToe, his 8' x 4' design using chain drive.
If you want to go with leadscrews you will need a ballscrew of 25mm diameter with fixed bearings at each end holding the screw in tension. With a 5mm pitch this will give you 1200mm/min (50ipm) cutting speed and 3200mm/min (125ipm) rapids (limited by screw whip) using an 8Nm NEMA34 stepper with decent drivers (50 or 60volt drives).
For the short, 4', axis a 16mm x 5mm ballscrew simply supported and a 2Nm motor would suffice.
By the way, thanks for supporting the efforts over at buildyourcnc.com. This is my first post on this site.
Welcome to MyCNCUK.
I note from your site you achieve 1500ipm rapids on BlackToe, thats pretty impressive!. What cutting speed do you generally recommend?
What size motors do you use for the X-axis to get these rapids and what is the gantry weight on your BlackToe design? Assuming you drive it from MACH3 can you say what acceleration values you have set up for cutting and rapids?
BUILD LOG: New Build - For Your Amusement - MK-2 buildBy Karl in forum DIY Router Build LogsReplies: 11Last Post: 11-06-2012, 07:34 PM