MILLING MACHINE (MILLMASTER CNC)

Table of Contents



Introduction

The MILLMASTER turret milling machine is a manual knee-type mill that has been retrofitted with a Fagor 8040MC CNC (Computer Numerical Controller). As such, the machine is somewhere between a manual mill and one that is completely computer controlled.

The milling machine consists of the following components:

  1. Tool changer (a manually activated pneumatic drawbar)
  2. Spindle speed control (a manual handwheel for continuous speed adjustment + hi/neutral/lo range lever)
  3. Spindle brake (manual lever)
  4. CNC (controls the quill depth, spindle on/off, table X-Y motion, etc.)

The most complex of the components is the CNC, shown here, and you must read up on it before using the machine. Navigating the various CNC screens is not at all obvious, but is straightforward once you have learned the key sequences. The milling machine, itself, is easy to operate.

Click on the image to see a larger version. (File size 464KB)

You will find on-line recommended reading material to fast-track you to being able to operate the milling machine.

Back to TOC


FAQ

Q: Do I need to know CAD/CAM to make a complex part?

A: Perhaps not. The CNC has a graphical interface (called the conversational mode) which allows one to make many parts without knowledge of CAD or CAM. Provided that your machining requirements may be described as a sequence of machining operations that are predefined in the CNC's library (called cycles), all that you need is an accurately dimensioned diagram or sketch of the part that you need to make.

Q: Can I do manual machining?

A: Yes, in JOG mode.

Q: Where do I start?

A: Below are suggested readings that should fast-track you to becoming familiar with operating the mill, CNC machining principles and the CNC.

Turret Milling Machine Operation Manual

  • Basic Machine Specifications (p. 3)
  • Operating Instructions (pp. 14-20)

Self-teaching Manual (MC Option):

  • Chapter 1: Theory on CNC machines
  • Chapter 2: Theory on tools
  • Chapter 3: Hands-on training
  • Chapter 4: Automatic operations
  • Chapter 5: Summary of work cycles
  • Chapter 6: Conversational part-programs
  • Appendix I: Programming examples

Note that our CNC has a different keyboard layout than that shown in the manuals. The self-teaching manual refers to sections in the operating manual, which is in the same PDF document. You will get a better understanding of the CNC if you read the relevant sections of the operating manual as well.

The operating manual is a bit weird particularly in the beginning sections as it mixes operating key sequences (what you would do as the user) and their relation to variables and programs in the CNC's PLC (what a technical support representative from Fagor would tweak.) Ignore the PLC details in your readings, as they only distract from the goal of learning how to use the CNC. (This would be akin to learning how to use an application as opposed to learning about its source code.)

The hybrid nature of the system makes reading user manuals somewhat awkward, as some parts of the MILLMASTER manual are now irrelevant and some functions of the CNC cannot be used with the hardware that we have. (Examples: Manual quill feed is disabled on the mill because the CNC takes care of this, though adjusting the spindle speed remains a manual operation despite the spindle speed being shown on the CNC screen.) See the manual section on this page for more information on disabled features.

Q: How do I turn on the milling machine?

A: This document details a typical startup and shutdown sequence for the mill. (The instructions presume that you are familiar with operating the CNC.)

Q: How do I transfer programs between the CNC and a computer?

A: Use Fagor's WinDNC software. Click here for more information.

Q: What is the policy regarding a program left in the CNC's memory?

A: Somebody will eventually delete it without notice. (See How do I transfer programs between the CNC and a computer?)

Suggestion: Include your name in the name of your program so that ownership is clear. You stand a better chance of being contacted before your programs are deleted.

Q: How do I generate Fagor code from a CAD file of a part?

A: We have a post-processing file for MasterCAM that will generate Fagor 8040MC ISO code. The post processor is actually for the 8055MC controller but has been tweaked to be compatible with the 8040MC. The file may need more tweaking. (Always do a dry run to check the generated ISO code.)

Back to TOC


Ways to operate the mill

Hand operation (DRO)

Impractical.
In principle the CNC may be placed in a digital readout mode (DRO) by touching the key with the symbol of a hand. This turns off the X, Y, and Z drive motors, but the CNC continues to display the X and Y coordinates as read by linear scales. The table can be easily displaced in X and Y using the handles. The quill is the problem. Firstly, there is no Z-axis information since this is reported via the motor's encoder — which is off. Secondly, it is very difficult to move the quill with the quill feed handle.

JOG mode (manually with CNC)

This is equivalent to hand operation but is a nicer way of doing manual operations. Operations are limited to displacing the tool in one of the three machine axes at any time. Here are a couple of examples.

1. Use the X+/-, Y+/-, and Z+/- keys to move the tool in one axis, alone. Observe the coordinate value on the CNC display and release the key when final destination is reached. (This is akin to rotating a table displacement wheel by hand, but by remote control.)

2. Say that you wish to mill a slot along the X axis and that a 50mm travel is required. Position the tool at the starting point (call this the origin.) Set the machine's X-coordinate to zero (type in X 0 <Enter> <Enter>). Now instruct the machine to move the tool by +50mm (type X 50 <Cycle Start>). Done.

In all cases, the tool moves at the feed rate set in the CNC. See Chapter 4 of the Self-teaching manual and Chapter 2 of the Operating manual (both in the same document.) The mill is not equipped with an electronic handwheel.

Automatic operations (cycles)

While at the CNC, you touch icons on the keypad which bring up a native graphical user interface. From here, you select one of several automatic operations built into the CNC. The graphics screen presents a generic form into which you enter, at the keyboard, the defining dimensions for the particular cycle. This is called conversational programming.

Examples of cycles include milling pockets and profiles, surfacing, drilling, drilling on an array or at multiple points, etc. For a circular pocket, the required form data is pocket radius, depth, tool to use, cutting speed, and so on.

Cycles may be assembled into a parts program. Programs may be offloaded from the CNC onto a computer for future use. Cycles and programs may be graphically simulated before execution to check for programming errors.

Programming by ISO code (G-codes)

The CNC may also be programmed using its own language (called ISO code.) ISO code is to MATLAB scripts as cycles are to Simulink models. Programs may either be manually entered at the CNC console or may be developed on a computer and uploaded to the CNC. Programs may be graphically simulated before execution to check for programming errors. A program is not lost when power is shut off to the CNC.

Sample programs may be found in the library section. See the programming manual for more detail.

As with any machining operation, you also need to give thought as to how the raw material will be held during the machining process (e.g., clamped to the table or held in a vise) as well as corner limitations as a result of tool radius. It is easy to design a part that cannot be manufactured.

Back to TOC


User tips

This document lists reported CNC idiosyncrasies, user tips and how-tos. It is a good idea to have a copy by your side when you are at the mill.

Back to TOC


Communicating with the CNC

The CNC is able to work in DNC (Distributed Numerical Control), enabling communication between the CNC and a computer to carry out the following functions:

  • Directory and delete commands.
  • Transfer of programs and tables between the CNC and a computer.
  • Remote control of the machine.

The CNC has an RS-232 serial port on its right-hand side and is also connected to the department's LAN. Both may be used with DNC software to communicate with the CNC and we use Fagor's WinDNC software to do so.

WinDNC configuration for Internet access to CNC:

  1. Install Win DNC ver 4.0 or higher (Win 9x/2000/NT/XP)
  2. Run Win DNC
  3. Click on the Setup icon
  4. Click on the New (+) icon. Fill in fields as follows.
    Name: MILLMASTER-CNC
    Model: 8050 M/8055 M
    Type: Network Node
    Connect on Start up: Leave blank
    IP address: xxx.xxx.xxx.xxx (fill in appropriately)
  5. Back at the Devices main menu, click on MILLMASTER-CNC.
  6. Click on the Connect icon

Hit Esc on keyboard to get back to main menu.

Back to TOC


Library of ISO programs (G-code)

For those inclined to try some simple ISO programming, here are examples of hole patterns used to mount common connectors onto instrument panels.
 
Click on an image or the links next to it to download a text file containing code snippet showing how the hole was programmed. Figures show a top-view of each hole.

Banana jack (standard)

   

Mastercam version


BNC bulkhead receptacle (Amphenol 31-10)

   

Mastercam
version


 

DB receptacle Front Panel Mounting Rear Panel Mounting

Back to TOC


Software

The department has the following application software:

  • Mastercam X4 + post processor for our Fagor controller
    We have one, sinlge user license which is locked with a sim (a hardware dongle.)
    The sim needs to be connected to the USB port of the computer running the application.
  • ProENGINEER
  • Fagor WinDNC (for communicating with the CNC from a computer.)
    This is a free download from Fagor's web site. (See contacts.)

Archives

Back to TOC


CNC customizations

The programming of the CNC has been altered by Fagor Automation Canada to provide the following features.

Tool-change X-Y coordinate (Implemented Jan. 21, 2005)

By default the tool change operation does not move the tool to the (X, Y) coordinate specified in the Change position window. It only retracts the quill to the correct height to allow the pneumatic wrench to engage the drawbar. This is a safe operating mode as it avoids tool collisions with other parts on the table since the table remains immobile during a tool change operation (T<n>). (The Z coordinate in the Change position window is not used with our machine setup.)

To enable use of the X-Y coordinate execute: M20 (this is a modal command)
To disable use of the X-Y coordinate execute: M30

Examples:
 
1. In an ISO program, place an M20 command at the start of the code to have tool change occur at a user-specified coordinate (X, Y). Otherwise, omit the M20 statement to have tool-change operations retract the tool only.

2. In manual mode, enter ISO M20 <Cycle Start> to enable variable tool-change point.

Changing working units (inches/mm)

To change working units press in./mm button and follow on-screen instructions. Then, reboot the CNC by pressing SHIFT-RESET. Incremental moves will not be as expected if the CNC is not rebooted.

Example:
Say that the CNC was working in inches and that you had switched to metric mode. If the CNC is not reset then an intended incremental jog of 1 mm actually produces 2.54 mm of motion.

Confirmation of spindle RPM speed (Modified July 31, 2008)

Whenever the spindle speed set point is changed the controller now asks the user to confirm the new setting by hitting <OK>. This gives the user the opportunity to set a new speed manually before continuing to machine. Also, a 3-second delay has been introduced between quill motion and sprindle turn on. This allows the spindle to ramp up to maximum speed before any tool move.

Back to TOC


Manuals

Mill (MILLMASTER Model 3VK with Vari-Speed Milling Head)

The following features of the mill have been disabled/removed as a result of the CNC retrofit:

Quill feed handle, quill stop knob, quill feed selector, micrometer adjusting nut and locknut, feed control lever, manual feed handwheel, forward reverse switch, power feed engagement crank, and feed reverse knob.(All features are located about the mill head, where the Z-axis drive is implemented.)

In principle, the quill feed handle may be slipped back onto the mill to allow the quill to be moved manually when the CNC motors are powered off. But it is imperative that the handle be removed before resuming CNC operation, otherwise the handle will spin violently as the CNC displaces the quill which will most likely cause damage to either the operator or the mill.

CNC (Fagor 8040MC)

Drawbar

Filter/Regulator/Lubricator: FRL

Back to TOC


Supplies

Milling machine components

Air-tool oil

  • Air Lube 10W/NR (ISO 22)
    Supplier: McMaster-Carr (Cat. No. 1298K51)

Way lube

Back to TOC


Maintenance

Parts

TAI YAN Machinery Co. Ltd., the milling machine manufacturer, appears to no longer exists. However, the machine seems to be the same as a TopWell 3VK; both machines have the same operation manual. The Canadian distributor of TopWell machines is HH Roberts Machinery Ltd.

Pneumatic motor

  • Make sure that the FRL is working properly with 1-2 drops every 5-10 motor cycles. One motor cycle is in and out once.
  • Make sure that no screws have vibrated loose. Tighten loose screws.

To disconnect air hoses: Push the hose (tube, air line) into the connector. Note that the collar ring also moves closer to the connector. Hold the ring against the connector and pull out the tube.

Drawbar

  • Under commercial use, each month grease the drawbar threads and area where washer sits with high-pressure grease, such as moly-lith.

Contact

  • For service on mechanical components of the milling machine (not the controller or connected components) call Service Jetec or Seguin Machinery.

Back to TOC


Contacts

Fagor Automation Canada
Montreal Branch
Tel: (450) 227-0588
Fax: (450) 227-6132
web site

HH Roberts Machinery Ltd
1324 Matheson Blvd E.
Mississauga, Ontario,
Canada, L4W-2Z7
Tel: (905) 624-5536
Fax: (905) 624-9065
web site

Le Groupe Magneto
1375, Gay-Lussac
Boucherville (Quebec)
J4B 7K1
Tel: (450) 655-2551 (South Shore)
Ext: 1-800-mag-hydr
Fax: (450) 641-4348
web site

Kurt Manufacturing (Workholding)
Tel: 1-800-328-2565
web site

Seguin Machinery
1306 rue Basin
Montreal, QC
H3C 1W2
Tel: (514) 935-3531
Fax: (514) 932-4459
web site

Service Jetec Inc.
Tel: (514) 648-5485
(This company has not been used yet, but was recommended by Seguin Machinery.)

Back to TOC

Last Modified: 2010-06-08 Ross Wagner


BME home
Back to top of page