Introduction: My First CNC Machine
This CNC was created using parts bought though the Kickstarter project www.aquickcnc.com.
Here is the Ended Kickstarted Project https://www.kickstarter.com/projects/ajquick/cnc-b...
The Design was built using Aluminium profiles and 3rd printed parts.
The great part of the design of this is that the Accuracy required for the project is designed in by using 3D printed parts. This was crucial for me as I don't own any equipment that would allow me to drill and cut accurately. the whole project was completed USING HAND TOOLS ONLY!
Step 1: Parts List
8 x 3/4" Linear Rod Rail Shaft Support For Cnc ***
4 x 3/4" rails 2x12" 2x24" http://www.aquickcnc.com/store/linear-bearings-an... ***
2 screw rails 1x12" 1x24" http://www.aquickcnc.com/store/
(alternative lead screws http://www.acculeadscrews.co.uk/acme-lead-screws/5...)
ACME Nut Bracket http://www.aquickcnc.com/store/building-blocks/acm...
Linear Bushing slide http://www.aquickcnc.com/store/building-blocks/lin...
Rounter Mount http://www.aquickcnc.com/store/router-mounts/bosch...
Stepper Motors http://www.aquickcnc.com/store/stepper-motors/bipo...
Motor Coupler (3/8" to 1/4") http://www.aquickcnc.com/store/mechanical-componen...
Microswitches x6 http://www.rapidonline.com/Electronic-Components/...
Crimp Connectors http://www.rapidonline.com/Cables-Connectors/Insu...
Plugs to fit socket x4 (order some spare too) http://www.rapidonline.com/Cables-Connectors/Low-...
Ordered from http://www.metallin.co.uk/shop/series-6 These parts from Metallin ordered cut to size and drilled. I Ordered all my parts cut to the correct length as I don't have a suitable method for cutting accurately
60x30 = 12" + 0.375" + 0.375" = 12.75" = 323.8mm x 2 (gantry bottom+ top)
60x30 = 24.75" + 0.375" + 0.375" = 628.65mm x 2 (Table length) with hole each end to attach universal connector
60x30 = 12" = 304.8mm x 2 (verticals) (Order End caps also x4)
120x30 = 12" = 304.8mm x 2 (ends) (Order End caps also x4)
T-Slot Nut 6 St M6
Standard Connector Set 6
bearing 3/8 x 7/8
Step 2: Design 3D Printed Parts
Using a 3d CAD software i designed the Brackets that would hold the Guide rails in place.
I also needed a part to mount one Stepper motor on the side of the Gantry.
The great thing about this is by having this part printed the accuracy of the design is printed in and does not have to be hand drilled in the workshop
my 3D print STL files can be downloaded here
Step 3: Drill Clarence Holes Fro Lead Screws
Drill holes in the Side Profiles and End profiles.
Because the Accuracy this 3D printed into the design the holes just have to be larger than the screws (3/8")
Step 4: BUILD TIME
Using a Tap set tap out the holes were required so you can use the T fasteners http://www.metallin.co.uk/shop/series-6/fasteners-..
then just take your time and screw all the parts together.
Step 5: Fit Emergency Stops
Using the switches Screw them in place so they will activate when the CNC machine reaches the end of its travel.
Wire the cables so it is NC (Normally Closed) that was if there is a short circit the CNC machine will fail to a safer position.
I had to add additional wiring to my control box for the Emergency stops.
Step 6: Calculate Steps Per MM for Mach3 Settings
Now I used this website (http://www.prusaprinters.org/calculator/) to calculate the correct Steps Per mm
the step angle of my stepper motors is 1.8°
the stepper motors are connected directly to the Lead screws so gear ratio is 1:1
and the CNC controller is set to 1/4 Stepping
my results were as follows
for the Z axis
9.53mm (2.11mm Lead) ACME Lead Screw
Steps per mm 379.47
for the X and Y axis
9.53mm (5.08mm Lead) x 381mm ACME Lead Screw
Steps per mm 157.48
Step 7: FINISH
I finished the design by adding a MDF work surface. This allows the bench surface to be easily replaced and flexible for fixing items to the base.
The last step is to connect it to a computer with a parallel port and run :)
Get a copy of the user manual for Mach3 (soon to be Mach4) spend lots of time reading and understanding the documentation. http://www.machsupport.com/help-learning/product-m...
Good luck and have lots of fun.
Step 8: Extra Step - Build Enclosure
Ok so its finished but it cant stay on my living room floor Until i get a bigger home!
So I needed to build a case so i can move it safely and look after all the kit
I built a rough box (using what material i had laying about) so the electronics could sit inside in a relatively dust free environment
The Machine can then sit on the top and the wires pass through to the machine.
Step 9: First Cutting Run
Its is a reasonable First effort BUT there are some learnings....
1. There is Backlash/play in the Y axis casing errors. It is currently fitted with just a normal ACME Nut. I have placed an order for an AntiBacklash Nut so i can replace it.
2. The Gantry wobbles when moving in the Y Axis at high speed. This is because it is unbalanced. I have ordered a larger piece of Aluminium Profile so I can place the Centre of gravity in-between the two sleeves on the rails. additionally this will allow me to stiffen up my gantry more but will loose some cutting area.
3. I was initially receiving false Limit switch activations. The cause was traced to noise on the Limit switch signals. the reason for this I am unsure but it could be because I have not used Shielded Cables. To overcome this i have added some DeBouncing Code to the computer software to overcome this.
Step 10: Adding Router Speed Control and Emergency Stop Switch
I have used the UK equivalent to the Colt router which is a fixed speed router. This has given me an new problem... Spindle Speed control.
So what I have done is install the Kemo AC Power Control Module inline with an emergency stop.
I also connected one of the parallel port pins through the emergency stop.
this means in an Emergency when I press the button a stop signal is sent to the CNC controller and cuts the power to the Router.
The speed controler cannot tell you how fast the spindle is spinning.
additionally on some fixed speed routers the cooling is dependent on the router running at full speed. thus running the motor slowly for an extended period can cause the motor to overheat and burn out.