... milling alloy would be nice but not a requirement.
a realistic decision!
the design will be a moving gantry with a workable area of roughly 2' by 4'. that is not set in stone and may be changed later as i work out the details.
the bulk of my budget will go on a controller/stepper package. i do have some electronics training but i wouldnt be confident in the reliability of anything i could build. since this is an important part of the machine i guess i should get this part right. i dont want to spend hours trying to get the machine working only to find the controller isnt working right. i am looking at a kit from
http://www.diycnc.co.uk/html/cnc_systems.html
it is the three axis kit for £207 i am looking at.
if anyone has any feedback on these products, good or bad, i would be interested in hearing it.
The DIYCNC package is used by several of our members and is well thought of, as is its proprietor. For your needs, if budget is an issue, you might consider his earlier System3 single board unit at £97. Dont forget you will need to add a power supply if you dont have something suitable to hand. Look for 30v at 8 - 12A, these can be picked up on eBay relatively cheaply (like this one, get in quick) or DIYCNC do a 24v one at £50.
the machine will be primarily constructed from mdf. i do have a table saw, router table, pillar drill and some other stuff so i shouldnt have much trouble making the chassis. i will keep an eye out for some second hand linear bearings and lead screws but for the moment the good stuff is out of my league so i will attempt to make my own. i will design the chassis with a view to maybe upgrade it if i get the chance.
With the savings on the controller you might consider Igus' Dryline-W bearings. I've not used these but the rail is £52/m and the bearing blocks under £7 so pretty price competitive to ball linear bearings.
my idea at the moment is to use threaded rod and make a delrin or nylon nut, use some ball bearings at either end and see how that works out. i understand that direct drive of a threaded rod will limit my feed rates but i am thinking i might try to gear it somehow, anyone any experience with this method? also i do understand that ball bearings will not handle the thrust loads and that is something i will look into.
Threaded rod will work, but with a 1mm pitch its really very slow. I'd recommend you look at TR12x3 (which is around £12/m from Marchant Dice on about 4+ weeks delivery at the mo) if you plan to make your own delrin nuts (you need a 100mm bit of rod to make a tap). Igus also do TR10x3 which may be cheaper but no prices on their site, have to request them (let me know what they are if you do). For 10 or 12mm rod at the speeds you likely to get you can get away with bearing support at the motor end only with a single ballrace and a thrust bearing. Technobots do cheap thrust bearings at 8 and 10mm ID.
on the linear end of things i am thinking of getting some nice straight angle stock, probably alu, and making a linear bearing like i have seen on some builds here....
the idea has been done before and works well if you have the constructional skills
...it will be well into the new year before i put blade to wood because i want to have a clear plan.
some people say, "dont think it, do it", but i agree a plan never hurts...even if you dont keep to itlol
Last Activity: 17-03-2017
Originally Posted by wires
Reply With Quote
Bookmarks