Mechmate #74 Hackland User Guide

Troubleshooting – problem solving when running the machine
Resources – templates. cutting tools libraries, useful scripts and add-ins for Fusion
About the Mechmate Project – description about the machine which is a homemade machine
Training – link to meetup page for fortnightly training sessions
Workflow – typical guide to workflows for design to machining
Setting up a job – how to setup a job
Mechamate #74 – history of the machine at hackland

Resources

As I show people how to use the machine. I am recording the sessions, check out the playlist at:

We will add new videos as they become available.

These are libraries of configuration files for the setup at Hackland. Recommended that these are used to avoid problems.

2D CAD Design Template

Template for designing primarily 2D objects. Setout on 2440 x 1220mm sheet (same size as CNC). Layers prepared for likely different tool operations.

2D CAD Design Template

Fusion360 Machine Definition

This file contains data about the CNC machine for use by the post processor. It IS NOT necessary to create valid GCODE but may help show warnings for operations that are invalid for the machine.

Machineconfig

Configuration file is available at:

https://github.com/cstewart000/HME_Mach3/blob/master/MechMate74.machine

Fusion360 Post Processing

This post-processor removes G43 commands which is “TOOL HEIGHT COMPENSATION” on some machines that used fixed tool holders, the spindle position is known and the length of the tool is taken from the tool library and used to determine the end of the tool position. In the case of this machine, we are using manual tool chaning with spring collets to fix the tool so the tool height is highly variable. Thats why the tool “zeros-off” on the aluminium touch block after every tool change. This helps provide consistency for the Z height.

My post processor removes all calls to G43 (standard on Mach3 post processor)

https://github.com/cstewart000/HME_Mach3/blob/master/mach3mill-NoG43.cps

Post processor needs to be saved into:

C:\Users\\AppData\Roaming\Autodesk\Fusion 360 CAM\Posts

Capturehelp: https://knowledge.autodesk.com/support/fusion-360/learn-explore/caas/sfdcarticles/sfdcarticles/How-to-add-a-Post-Processor-to-your-Personal-Posts-in-Fusion-360.html

Fusion360 Tool library

Fusion 360 Cloud tool library (Automatically Updated) – https://a360.co/2IS9ZXF download the library to your machine. Open the tool manager, and right click on the local tab. Select import and navigate to the downloaded library.
Tools are (meant to be) the sasme in the mechmate configuration, so things should align.

Fusion360 Standard CAM operations

Fusion 360 Operations template (Use these to automatically import a series of operations when doing a CAM setup) – 2.5d typical wood operations: profile, drill, pocket etc. https://a360.co/2kwB0Rx

Fusion360 Dogbone tool

This is a tool for creating “dogbones”into  internal corners of parts. This compensates for circular cutting tools not being able to reach the material inside of a tight corner.

dogbone_002-1520512717

source: http://wiki.imal.org/howto/dogbone-fusion-360-plugin

https://github.com/caseycrogers/Dogbone

Download this file and extrract to: C:\Users\{USERNAME}\AppData\Roaming\Autodesk\Autodesk Fusion 360\API\Scripts

Fusion360 – Mapboards

Map boards is a paid add-in to help layout components onto a single plane for machining. The add-in is accessible throught the Fusion360 App store and costs $2. It is well worth the time savings.

A free alternate that doesnt work very well is called “Nester”.

Mach3 – Macros

The CNC machine uses a series of Macros to control the behavior of the machine. These are called when the GCODE file runs a “M” code.

e.g. when the GCODE calls “M30” at the end of the file, this is the code to “rewind the tape” (remember NC or CNC is very old tech) and return the GCODE to the top line.

Another example is “T121 M6” which means: Load tool (T) 121, using “M6” tool change macro. In the CNC machines macro folder, there is a file called “m6.m1s” which is a VB script that performs the tool change proceedure.

All the macros are held on a github repo for changes/documentation, if there are any bugs with behaviours? Log an issue  at: https://github.com/cstewart000/HME_Mach3/issues/

Email to Machine

Send your gcode to mailto: mechmate74@gmail.com

Training

In person training is offered every two weeks at Hackland (as of March 2018).

Please check the meetup page for CNC classes. It is required that you attend the a few of these sessions to get comfortable with the machine

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Safety and Environment

The cnc is a powerful and potentially dangerous piece of equipment. It is important that safe use of the machine is a high priority for all users

Safety Features

  • E-stops on the machine ganty and car
  • Electrical Fire extinguisher
  • Operation manuals
  • Interlock on electrical cabinet
  • Soft stops
  • Residual current device

Noise Management

Be considerate of other users of the space. Try to set a job outside of busy times or when the space is empty.  Short jobs around 5 minutes long usually wont cause problems.

Please use hearing protection ear plugs/ ear muffs.

Dust Management

As above please be considerate of other users of the space. Make sure the extraction unit is working normally and the shrowed is in place to remove any particles.

There is also an air-filtering unit on top of the shelves above the member storage. Please turn this on to filter any fine particulate out of the air of the space.

Consider using dust masks when doing longer jobs to minimise exposure to harmful particles.

Workflow

To turn a part from an idea to a physical object, there are several steps that must be taken. First the component is designed in a Computer Aided Design (CAD) software package. Those designs are then brought over to Computer Aided Machining Softwart (CAM) which is used to generate the tool paths to mill the material into the intended product. Finally, this is passed to a mcahine control software that interfaces with the machine to control the inputs and outputs of the machine during machining.

CAD ==> CAM ==> MACHINE CONTROL

Computer Aided Design (CAD)

To machine objects they must be designed in a CAD program or other vector based design package. We recommend the following software:

For simple 2D objects: Draftsight a vector modeller and a clone of the popular AutoCAD, this is free software perfect for quick jobs with few parts, and low complexity in the third dimesnion

For more complex objects: Fusion360* Fusion360 is a solid modelling program that is becoming a leader in the product developement space. It is much better equipt to deal with complex 3 dimensional components.

*If you are serious about learning to machine Fusion is strongly perfered but requires a bit more effort to learn.

Lars Christiansen runs the most comprehensive Fusion 360 tutorial channel on YouTube. His introductory video is linked below.

Computer Aided Machining (CAM)

Vectric Aspire – If using any vector based tool including: Draftsight, Illustrator, AutoCAD etc, Vectric is the CAM software to use. A short quickstart video is included below.

Fusion 360 – Another advantage of fusion360 is the integrated CAM functionallity. The main advantage of this integration, is that if there is any change necessary in the model, the CAM can be updated easily to reflect those changes. The alternative would mean switching software packages and re transferring files each change nomatter how minor.

NYC CNC is another very good Fusion 360 tutorial channel on YouTube. Lars also covers this topics on his channel.

Machine Control

Mach3 – Mach3 is the installed software on the CNC machine currently. It is likely that a switch will be made to the latest version Mach4.

Setting up a Job

Material

Placement and Restraint

Make sure to provide enough screws to hold the job flat to the surface. I good rule of thumb is one screw every 500mm or so. If you are using very thin material or material that has a bow, you may need to decrease the spacing to pull the stock true.

It is highly recommended that you model screw locations in your layout and drill the screw locations USING THE MACHINE. If you do this, the likelihood of accidentally milling a screw is very low.

Loading the File

Send your gcode to mailto: mechmate74@gmail.com

Open your gcode file>open,

You should see a render of the job on the right hand pane. Make sure the job is oriented correctly.

Final Checks

  1. Check spindle coolant levels (red tank under the table next to control box)
  2. All rails and table clear of obstructions
  3. Check job restrained effectively
  4. Jog machine to the bottom left hand corner of your job and set co-ordinates to X=0 , Y=0 (Dont worry about Z-axis, this zeros automatically when the tool zeros).
  5. Override feed rate to 10% when job is starting (return to 100% when job is running as expected.
  6. Check GCODE and trace the job to make sure if all fits on the stock

About the Mechmate Project

The Mechmate is a project designed by a South African machinist/ engineer who wanted an alternative to the popular shopbot which was one of the original high-end hobby low -end commercial affordable CNCs. A ShopBot of similar size retails for around $22,000 USD http://www.shopbottools.com/

The project has been running since 2006 and has a vibrant support community which can be consulted to service the machine. http://mechmate.com/The forum also contains builder projects if interested. Up to now, there are 127 of these machines worldwide. Machines are tracked on a register: https://docs.google.com/spreadsheets/d/1SDSq8C8mQKJzp0oTrXtHcTYXp_QmFlYev9zRc1X2nZE/edit#gid=0

Mechamate #74

This particular machine is serial number #74 built in Queensland Australia by an ex-surfer. The machine was constructed primarily to help carve surfboard foam blanks. Videos of the machine working can be found it the ex-owners youtube channel https://www.youtube.com/channel/UC9W_CHsB8LTcB6p4n339KvA The builder also made some components successfully with sheet aluminium https://www.youtube.com/watch?v=iaAz2-9EP9c

A fast motion video of the import of the machine to hackland

Some specifications

  • Overall dimensions: 3110 x 2220 x 1800mm
  • Antek Power supply
  • PMDX122 Driver Board
  • ESS Smooth Stepper
  • Leadshine DM856 digital drivers
  • 34HS9801 Stepper Motors
  • Water-cooled Spindle (2kW)
  • Variable Frequency Drive
  • Computer with drivers and CAM software
  • Wireless controller – xbox controller for jogging the machine.

Hardware

In the class we will give a d detailed explanation of each element of hardware and function including:

  • Cooling system
  • Dust management system
  • Clamping/restraint
  • Electrical
  • Overview of electrical system. Dangers etc.
  • Electronics
  • Overview of the control system
  • Software
  • CAD=>CAM=>GCode tool chain.
  • SAFETY AND GOLDEN DO NOTs
  • Hearing protection

Troubleshooting

Logging problems

Please email any faults or problems to mechmate74@gmail.com. This will help find common problems and create longer term solutions.

The machine moves out of range in z axis and triggers an estop

The likely problem is that you are using TOOL HEIGHT COMPENSATION – This is where the code accounts for the length of the tool and offsets depending on the hieght. Since our system is setup to use the BOTTOM OF THE TOOL as the datum AND that tools are installed MANUALLY, tool height compensation is not approriate on this machine.

Look for a line in your code starting with “G43” (this is the tool height compensation setting).

Short term fix:  Edit you GCODE file to remove tool height compensation.

Long term fix: Use the post-processors that have been edited to exclude tool height compensation.

https://github.com/cstewart000/HME_Mach3/blob/master/mach3mill-NoG43.cps

 

When the machine homes, it makes a clicking noise and hits the endstop 

The likely cause is a faulty proximity switch. These are cylindrical sensors that detect changes in magnetic field. They are supposed to open when there is no steel in front of them, and close when there is. Unfortunately, these switches can be a little finiky and can through false positives and false negatives from time to time.

To diagnose the problem there is an indicator LED on the back of them. This will tell you the state of the switch. It should be lit when anywhere in the normal range of travel.

  1. Using the remote controller SLOWLY jog ONE AXIS AT A TIME of the machine towards home. The the light should go out and the machine should stop when the switch moves off the steel section in front of it. An e-stop will have been triggered.
  2. Clear it the e-stop. This axis is working normally
  3. Repeat for the other two axis.

Once you have isolated which switch is not behaving properly, adjust the two ring nuts until the sensor is at the right distance to behave normally.

Please also send an email to: mechmate74@gmail.com logging the change.

You can check the state of these homing/limit switches in mach3. Go to the diagnostics tab.

The Machine Zeroes the Tool then Moves up and an E-stop is triggered.

Please check the Z axis limit switch. If the light is out, the machine may have moved out of its operational range. This may be because you are using a long tool, or that you have large clearances over the workpiece.

The GCODE that you have generated is telling the machine to raise the tool above the workpiece by a certain distance to stay safely above it. Consider revising these clearances when generating the Gcode. 10mm should be plenty of clearance.

Clearance adjust in Aspire

Clearnace adjust in Fusion360

The Machine Zeroes but Suddenly stops and an E-stop is triggered

Check the line of code where the machine has stopped, it may be that the spindle is faulting. The spinldle has internal circuitry that allows it to E-stop if there should be a problem. In this case, it may be that the coolant pump and cooling fans are not active.

If this is the problem the fault would likely happen at a line in the GCode like this:

S12000 M3

This is the line setting the speed (“12000” rpm) and direction (“M3” = clockwise).

Please check that the pumps and fans are properly plugged into the relay outlet.

To verify that the pump is working, clear any E-stop and click on the mist on/off switch.

The pump, fan AND dust extractor should all turn on as they are all on the same circuit. You can silence the dust extractor by hitting the stop button to listen for the coolant pump.

The machine should automatically switch on the relay for pumps before turning on the spindle, if the pumps come on and the spindle E-stop is still triggered, please wait for a short period (10secs) after pumps start before pressing cycle start. This will allow fluid pressure to reach the spindle and prevent the E-stop condition.

The Machine is not Cutting in the Correct Location

Please check the Job co-ordinate has been correctly set. Toggle between the MACHINE and WORK co-ordinates using this button.

The Digital Read Out (DRO) for the MACHINE co-ordinates should read

X: 0.0000

Y: 0.0000

Z: 0.0000

when homed. Please note that Z: 0 for MACHINE co-ordinates is with the spindle fully retracted (i.e. at the top of the work area)

Make sure the DRO is toggled to WORK co-ordinates. Jog the machine to the corner of your job. Hover the tool just above the workpiece. The DRO should read:

X: 0.0000

Y: 0.0000

Z: Your material thickness + whatever height you are above it

The Spindle does not start

Currently not 100% sure what is happening here. The spindle is run off a different COM port and plugin then the rest of the machine. This seems to cause numerous issues. if you have had to stop the job while the spindle is running. The spindle may not start up next time automatically.

If the water pump  OR ATC fans are not running the Spindle will call a fault and trigger the E-STOP.

Current work arounds:

  1. Restart the job (turn it off and on)
  2.  Feed hold (spacebar) the job after the tool starts its first jog after touching off the zero plate.  The tool should Stop!
  3. Press the spindle override control (below).  The spindle should start running at the speed instructed in the GCODE.

Mach3 Spindle Override

4. Press cycle start.

Anything Else?

Log an issue at: https://github.com/cstewart000/HME_Mach3/issues/

or email

mailto: cstewart000@gmail.com