MILLING MACHINE (MILLMASTER CNC)
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:
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.
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.
A: Below are suggested readings that should fast-track you to becoming familiar with operating the mill, CNC machining principles and the CNC.
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
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.)
A: Use Fagor's WinDNC software. Click here for more information.
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.)
Hand operation (DRO)
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.
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.
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.
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.
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:
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:
Hit Esc on keyboard to get back to main menu.
For those inclined to try some simple ISO programming, here
are examples of hole patterns used to mount common connectors onto instrument
Banana jack (standard)
BNC bulkhead receptacle (Amphenol 31-10)
The department has the following application software:
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)
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.
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.
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.
Milling machine components
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.
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.
Fagor Automation Canada
HH Roberts Machinery Ltd
Le Groupe Magneto
Kurt Manufacturing (Workholding)
Last Modified: 2010-06-08 Ross Wagner