Hello Open Builds, i am all new to this,and realizing the irony in this is to build a cnc you need a cnc. any ways my names liam did a betc many years ago and touched on cnc stuff then went to uni did motorsport engineering again touched on cnc and manual maching. i have always had an interest in cars bikes how thing move how they are made (my dad is a retired mechanic) so i have always been around tools and gagares. i am now a CAD technican (unfotuantely all 2d stuff) but i like playing in 3d. Most recently designed some parts that i had 3d pritned. Milling/cnc has always fascinated me and have started to notice allot of the DIY kits pop up on fleabay. Looking around at them they are great as they are relativity cheap to get started how ever i feel they are not always as well made as they could, more backlash (quote me if am wrong) and feel like if i build one from scrath i can 'over engineer it' if i wanted too. Again took me a white to find one i like, whilst browsing for machines i stumbled across this forum too. i have ended up settling for a desing i came across on indstructible Building your own CNC router/milling machine - All (all credit to Trochilidesign) heres his finished one i like this design because it was relatively compact, very well house and just looked nice.after reading through the step by steps.i started by just redrawing his one in cad to get a better understanding of how stuff works. (On a side note i am familiar with the metals profiles i build a cycle frame jig..its great stuff) When i made my frame jig i used a dutch company based in the uk called minitec, they were helpful quick and had what i needed. My next step was to draw up the machine using profiles minitec stock.et voila This is what i have achieved. i now at a point where i would like some help/guidance in what to choose, and understand certain aspects. This is also due to Trochili instructions being somewhat vague in certain areas seemed to just mention in a short sentence and move on. The ares i need help solving to get this machine to a point where it lives 1. Is the 'Lead screws or ball screws' on all axises. In Trochilis insturctions this all he mentions is "I chose to use leadscrews with a special plastic drivenut which reduce friction and are approach a backlash free system. You can order the drive nuts here: http://www.mixware.de/index.html\" The threaded shafts them selves are: X and Y - 16 x 9 thread pitch? Z -12 x 3 thread pitch? ideally after a one that i can get a cad block of so i can place it in my drawing make sure it works or amended the design to accommodate it See this like this on ebay quite alot x4pcs SC16 Housing + ID16mm Samic Linear Bearing CNC Custom 3d Printer | eBay 2. Pulleys and belts 'The pulleys are drilled to the turned shaft size (in my case 8 mm) and provided with a M4 setscrew perpendicular to the shafthole' again no mention oif size of the pulley or belt used. 3. Could i replace my bearing blocks with these? My bearing block below: Replace with these below? Kamp und Kötter - Lagerset für Kugelumlaufspindel 12mm to make it cheaper? i.e. use avaliable parts instead of having parts made?althou if i was having a bacth made they would be more expensive? 4. on Trochilis build theres is a part 'Y-axis nut late' cant work out were it goes if its needed? Sorry lot to digest and take in.also i am relatively new so might have to bare with me. Help would be really appreciated Liam
Hi, if you understand german i could explain at lenght... There are two types of leadscrews . The ones mentioned on Mixware are trapezodial and the "conector" to your axis would be a plastic block. These are sort of old fashioned but nothing bad or low quality. They are quite good for more traditional type of milling and not as good for 3d because of heating up when doing 3d finishing passes for hours- but their backlash can be readjusted easy. the second type being so called ball screws where the "conector" or screw is a type of special ball race sort of setup Better for 3d (less friction, less heating up). You get what you pay for so a ceap ball screw and nut will result in (a little) backlash which you have to compensate in your cnc program (alike Mach3 ...) The e-bay link goes to slider blocks for round "rails" these are a different form of the square type of rails and blocks (in your pics-the parts that actually allow the axises to move) The square types being actually far superior in terms of load capability and actually worth the money... Nothing to do with your 16/xx ballsrew The Kamp und Kötter parts are bearings to hold your ballscrew, you need a fixed and a loose end... read up on it And yes it is always better to use availibe parts over custom made ones hope that helps a bit flo
