Cheers for the great comments so far, I haven’t blogged lately been busy with selling my house trying to move on to bigger and better things I hope. I promise to add more soon I’ve got heaps more to tell on pretty much all of my catergories, I have only scratched the surface so far…

Best wishes to all

AF.

Steppers vs. Servos

Well, I have been asked this question by a few fellow hobbyists that want to get into building a CNC machine.

A few things to consider,

1. Budget
2. Complexity (How would you rate yourself as “technically inclined”)
3. Stock Size
4. Stock materials
5. Speed
6. Accuracy
7. Repeatability
8. Machine configuration

Firstly, I will discuss a little about budget and how this will affect the decision on which motor type to use, as a rule Stepper Motor’s are cheaper than Servo Motor’s but both types have their pros and cons and what we will try to do is determine a plan so we can make the right choice from the very start. (That said it is not too hard to change from one to the other at a later time)

Complexity

The greatest thing I suppose with a hobby CNC is that you can make it as simple as you like while you’re learning and experimenting with different methods, chassis types, control systems, driver systems and all the sub systems you would like to put in place.  There is no right or wrong as long as you follow the basics you can build on or improve your work, even make new parts on the machine to improve it… That’s always fun.

Just migrated straight from Windows XP?

Can’t find that blasted setting that you just need to adjust?

Well read on I will show you how to display all user configurable options in one convienient place..

All you need to do is create a New Folder, for me I have this on my desktop where its quick and easy to find, but you may like to put it wherever you like which is fine.

OK follow these steps;

1. Right Click anywhere on the desktop (for the purpose of this How to, you can move to anywhere afterwards)
2. Navigate to “New” in the options list, then again select “Folder”
3. This will then give you the option to rename the folder, now just cut and paste the following in step 4
4. GodMode.{ED7BA470-8E54-465E-825C-99712043E01C}
5. Then press Enter.
6. There you have it, now the icon should change to something like this below –

 
Now you may double click this icon and this will bring up a window with almost all settings the average user could ever need to adjust.
Hope you find this useful, I did.
XaserTech.
 

I have made automotive parts, motorcycle parts, computer parts mainly for liquid cooling and also replaced some OEM items with my own sometimes improved parts. and not only for me but family and friends and some paying customers which has been a help in further developing the machine. 

I use Mach 3 as the software to control the machine and Solidworks and MasterCam to design and code the products to be made, if you like you can think of the machine as a printer that makes actual usable parts. You draw it then if you like what you see you print it with some stock you specify be it, wood, plastic, metal or composites. 

I plan to make some CNC control boxes for other budding CNC’ers of the hobby market down the track once I further develop my machine, next on the agenda would be either Servo motors over the current steppers or a lead screw upgrade to a ball system just for added accuracy and repeatability. 

Mill during tuning and setup

Mill during tuning and setup

So there, shown above is my modified mill – now a fully operational 3 axis CNC machine. 

The Build 

This machine is based on the Hafco Metalmaster HM35 Manual Mill/Drill Press. 

I had chosen to go with Steppers with this machine because I knew at the planning stage I would opt for gearing down because of the nature of the compound table.  At the time speed was not much of a concern just needed a functional CNC mill. 

Being and Chinese copy the quality of the leadscrews weren’t  up to scratch there was heaps of backlash which I did manage to adjust most of  it out, only to discover the leadscrews are not uniform across their entire length which caused me a lot of grief with binding and sticking during rapid table moves.  So then I had to adjust the leadscrew nuts with a compromise between backlash and binding. 

With much use the gap of compromise has closed up as the leadscrew and nut bed in.  My next modification is Ballscrews and Ballnuts which cost a small fortune because of being  high precision parts, but improve friction and overall accuracy than the current trapezoidal jobbies in the machine presently.  Even though the machine did have a degree of backlash the improvement over milling by hand was tenfold in regards to speed and accuracy. 

My main reason to do this CNC mod was to basically take the mundane and human error factors out of making small parts and moulds by hand.  The benefit of being able to design your part on a PC and run a simulated toolpath to make sure all is good is a real bonus and also depending how you look at it, it can be quite fun. 

Assembly 

The machine when new or “out of the crate” so to speak is a Geared Head manual milling machine and drill press, there was a belt driven model but the risk of belt slipping during a cut and breaking tools was at a far more higher risk than a Geared model, the only real benefit with belt driven was that they run a little quieter.  

Now I need to get drive to the 3 axis X, Y, Z, the X and Y were my table controls and the Z being the “quill” or spindle.  I had to first determine the mechanics of driving each axis I had already decided to gear down the drives because I needed to increase the torque of the steppers I had already, 430oz/in NEMA24 Unipolar 1.8° Step Motors because of the gearing down ratio was 3.33:1 meant that 3.33 x 430 = 1431.9oz/in, yep that was plenty I thought. 

Now seeing that the manual wheels and graduated dials were now not needed as a human interface it was time to yank’em off and toss over the shoulder getting ready to measure up and start fabricating the bracketing to firmly hold the step motors in place while applying enough tension to the timing belts I planned to use.  At this stage I knew how I wanted the motors to mount to the machine but had no idea on the pulley sizes and belt lengths, all I knew is that this had to be well thought out so everything would fit together as I did not have the pulley or belts these were yet to be purchased once I knew the sizes and configuration that would work.

I took measurements off one end of the table where the leadscrew bearing housing mainly the hole centres of the bolts which pin the housing to the table, I preferred this idea as there was no need to drill and tap extra holes for mounting my custom bracket.  Once all the information was collected I turned to Solidworks (Parametric Modelling Software) which I’m fortunate enough to have access to and design a prototype of the idea I had of the assembly, from this and other data I could the determine the pulley sizes and belt sizes I would need to complete the model.  I followed the same principle for both table X and Y axis.  The Z was also quite similar except I took advantage of the broad space in the bracket I had to incorporate some control items such as the E-Stop (emergency stop) just in case your tie or scarf got caught in the spindle, your forehead as it was dragged into the machine would bump the E-Stop thus saving your neck.  You’d think it was strategically placed but as it turns out it was only a fluke that it ended up there.

Stay tuned…

Well I have a beef with my iPhone,  I tend to only use my iPhone mail client when I’m really expecting an important email and I’m on the road, somtimes this can be a few days between checking my inbox, but when I do, I normally have a flood of emails coming in but they are all marked as unread but 9 times out of 10 I have more than likley already read it on my office computer.  This isn’t my real issue it is the fact you have to view each email to mark it as read so I can clear the unread email count, what we need here is a “Mark all as read” option within the mail cilent, or in my case a mass delete option..

Would anyone else probably find this helpful also?  Let me know what you think.

See ya.

Xasertech Search Engine – go on give it a go..