Copyright (C) 1986-2008 by Daniel H. Hudgins, All Rights Reserved.

No part of "This Web Site" (HTML document), including associated files, may be: distributed, sublicensed, transmitted, copied, archived, mirrored, modified, bundled, embedded, sold, given away, rented, loaned, or shared in any form without express written permission in a formal Vendor agreement contract dated and signed in ink obtained directly from Daniel H. Hudgins by registered postal mail. All agreements for permission to distribute expire after a period no greater than one year from the date of the signing of the agreement by Daniel H. Hudgins. See the current "EULA" for information regarding limited copying and storage for the purpose of "Beta Testing" "This Web Site."

To view or use the current version of this Web page you may need to reload or refresh the display of this page by your browser. Just clicking on the browser's [Reload] or [Refresh] icon may not be enough to insure that all of the page's most current contents have been cached and displayed. Some browsers may have additional commands to help display the page's most current contents such as: holding down the [Shift] key and clicking on the [Reload] icon, holding down the [Control] key and clicking on the [Refresh] icon, holding down the [Control] and [Shift] keys and clicking on the [Refresh] icon, pressing the [Control] and [F5] keys, pressing [Control] and the [R] key, or some other combination of keys or clicks. Check to see which commands your HTML browser uses to load the most current page contents into its cache and then to display them onto the screen.

This Web site is dedicated to the thousands of "users" of my programs, those who have helped test my programs over the last 22 or so years, and especially those who shared their experiences with me.

You must read this notice: This is a licensed Web site (HTML document and associated files). You must read and agree to be legally bound in contract by the Terms of Use and conditions given in the End User License Agreement ("EULA"), Legal Notices, Instructions, Warnings, Disclaimers, and all other text in "SECTION: 0" of "This Web Site" (HTML document and associated files) before reading or using any of the information, software programs, and or files, contained in, linked to, and or associated with, "This Web Site" (HTML document and associated files). Any use or "Beta Testing" of "This Web Site" constitutes your acknowledgment of your full agreement with the current End User License Agreement ("EULA") and your decision to have this current license supersede all prior and contemporaneous agreements and understandings. Information and files in "This Web Site" (HTML document and associated files) have been placed here so that long time users of "The Author's" programs DANCAD3D.COM (tm) , DANCAM.EXE (tm) , or DANPLOT.EXE (tm) could help proofread the text of the documentation files or screens displayed, and also help test data files, example files, and or any software programs that might be made available from time to time, to aid "The Author" in finding mistakes, bugs, and other errors, omissions, defects, mistakes, and faults. Everything in "This Web Site" (HTML document and associated files) is "Beta Test", "Beta Code", Experimental, Preliminary, requires proofreading, or is being evaluated for possible revision, and is NOT warranted to be free of defect. To help "The Author" report any bugs, foul-ups, defects, or mistakes that you find, see "SECTION: 8" for instructions. "This Web Site" (HTML document and associated files) and all other files and programs by Daniel H. Hudgins are made available "AS IS" without warranty of any kind express, expressed, or implied. All offers and specifications are subject to change or discontinuation without notice of any kind. Please read "SECTION: 8" of "This Web Site" (HTML document and associated files) before trying to contact "The Author."

SECTION: 7.10 is for some "general" information about CAM, CNC, or NC type automated machine tools, see also the program files in the current distribution of my programs, the other parts of this HTML documentation, and the current On- Line version of this Web site for information more specifically about my programs. Any comparisons of my programs or methods to some others is only given as a vague generality of my opinion and is not intended as a recommendation or reference to any particular products, always make your own evaluations and comparisons before taking any action.

A CAM machine is a machine tool that has been automated so that it can operate itself. Machine tools are differentiated from hand tools in that both the tool and the work-piece are held firmly in place by attachment to the machine tool, and their position relative to each other can be precisely controlled by rotating graduated hand-wheels and such. A machine tool becomes a CAM machine, i.e. a Computer Aided Manufacturing machine, when rather than having someone rotate the graduated hand-wheels with their hands to make the part, special motion control electric automation motors are attached to the machine tool to turn the machine tool's shafts where the hand-wheels would normally be, and these special electric motors are operated by a computer that reads a set of planed movements for the tool's motion relative to the work-piece, and thereby manufactures the part without the direct labor of a machine operator.

In the early days of CAM the "controller" was a special purpose computer that read letters and numbers from a punched paper tape and moved the tool or work-piece around according to the numbers punched in the paper tape. Some NC and CNC type systems made today sometimes also use proprietary computers and hardware that cannot be used for other tasks.

My CAM software machine control programs, DANCAM.EXE (tm) v2.7 and DANPLOT.EXE (tm) v2.7, run on a general purpose IBM (tm) XT/AT (tm) compatible type of computer under DOS, or for some non critical applications sometimes under Windows 95 (tm), or in other cases under a "DOS 95" floppy boot disk. The speed of the computer you will need to use depends on how fast your automated machine will need to move and other timing considerations. An old "junk" 8088 computer might be fast enough for milling steel if you are not in a hurry. It can be advantageous to use a general purpose computer for controlling your machine tool, since proprietary computers and hardware may require expensive parts and labor to repair, whereas you can probably find "junk" IBM (tm) compatible computers for very little, or for "free," to replace the computer you have been using to control your machine tool when the computer burns out.

The tool path my software uses is generally stored in a drawing file on a floppy disk or on your computer's harddisk. With older NC machines the tool path was a series of codes punched into a paper tape.

The motor drive electronics used with my CAM software machine control programs connect to the computer through the computer's parallel printer port. Since the parallel printer port is TTL logic compatible it is possible to connect some brands of automation motor driver directly to the pins on the parallel port without any additional electronics. It is possible to damage or destroy your computer by connecting directly to the parallel port if you make a wrong connection or something goes wrong with the drive electronics or its power supply. Motor driver electronics that are optically isolated are safer to connect because there is no major electronic connection to the computer, the computer makes a small light, i.e. an LED, blink that transmits the signals for the motor rotation across the optical isolator to the motor driver circuits.

Two types of drive electronics generally are used with an automated motor, i.e. for a stepper motor, or for a servo motor. Stepper motors are a special type of motor that has coils that hold the shaft at fixed positions, when the current is switched from one coil to the next the shaft rotates to the next fixed position. In a stepper motor if you switch the current from one coil to the next quickly enough the motor looks like it is rotating rather than jumping from one position to the next position. Servo motor drive electronics can use a regular type of DC motor, that has an encoder attached to the rear shaft of the motor so the drive electronics can keep track of the shaft position and apply positive or negative power to keep the motor synchronized with the computer's movement signal commands.

The movement signal commands used by my CAM programs, and some others, are step pulse and direction signals. The computer first sets the direction signal high or low to tell the motor driver which way to rotate the motor's shaft. Then the computer sends step pulses to rotate the motor's shaft in the selected direction by an amount set by the number of pulses received from the computer. Such limited movement of the motors is sometimes called motion control since the movement is precisely controlled not only in the speed and direction but also in the absolute distance moved.

The machine tool that is operated needs to have some method by which the automation motors can precisely move the tool relative to the work-piece. Several methods can be used, such as, a lead screw and nut, a chain, cable or timing belt, or a rack and pinion. In general the method used must prevent slippage of the moved part so that the absolute position of the tool is always the same for a given number of rotations of the motor shaft. To make sure that the starting point is known by the computer the machine will generally have home switches installed, and the software will run the tool to the home position switches before the tool path is read. If home switches are not used then the machine would need to be "jogged" manually after the computer and electronics are turned on to a known point before the tool path is read.

The controller or computer operating the CAM machine generally has a special manual control screen so the machine operator can "Jog" the tool or work-piece into various positions relative to each other in order to set the starting point for execution of the tool path, to make set up measurements, or for other semi-manual movements of the machine. In my CAM programs you can make the Jog movements in several ways: you can enter the "go-to" coordinate values for the point to move to, you can use the arrow keys on the keyboard to move in increments in different directions, you can use the Joy-stick to move the machine at different speeds, or you can turn a hand-wheel encoder to move the machine at a speed related to the speed the hand-wheel is rotated at for the selected axis to move.

It is very important that CAM machine tools be very stiff since the position of the tool is relative to the starting point and any flex in the machine may make the parts manufactured be of the wrong size or shape. Existing manually operated machine tools can be "retrofit" with automation motors, electronics, and a computer, for automated operation, but may need to have the tool path file carefully drawn so that the flex of the tool is reduced in the final cuts by taking several light cuts. Commercial CNC machines are generally very sturdy. Older NC machines with "dead" controllers can sometimes be converted to PC control by connecting the parallel port to specific circuit points in the motor drive electronics if they are not the part that is burned out.

There is always some lost motion when the direction of cut changes, this is called "backlash." It is possible to "take- up" the backlash in software, my CAM programs have this feature, but the tool path file needs to be designed so that all the rough cut motions are back from the final line about double the backlash distance for each axis. It is possible to use special types of lead screws like "ball bearing lead", "anti-backlash", or use a adjustable "split" nut to reduce the lost motion on direction changes. When a timing belt or cable is used to pull the tool along, rather than using a lead screw, the pulley at the end opposite the motor can generally be adjusted to tighten the "slack" in the timing belt or cable to reduce the amount of backlash due to the slack in the timing belt or cable backlash.

Automated CAM machines can also be fit with electronic relays to automatically turn the spindle motor on, or to also turn on or off coolant pumps, electronic clamps, and such. Some solid state relays can be connected directly to the parallel port and are optically isolated. The three volts on the input connection of a solid state relay, obtained from the output pins of the parallel port, may be able to switch loads of up to 20 amperes 120VAC or more on the solid state relay's output side. Optical isolation between the computer and drive electronics reduces the risk of damage to the computer when the drive electronics fail, if you have a ground fault, if you have some reversed connections, or if there are other problems, since there is no "direct" electronic connection to your computer just a small light and a light sensor inside a small black plastic block of the optical isolator, the signal being sent on the beam of light inside of the optical isolator.

When my CAM programs are being used the control relays can be controlled by the tool path file to turn on and off at specific points while the part is being manufactured. The same idea applies to other CAM controllers, but the codes used may be different.

All CAM machines should be enclosed within a set of safety shields so that the person operating the machine, or anyone else in the vicinity, cannot put their hands, or body parts, near the moving parts of the automated CAM machine, or get hit with things flying out of the machine in normal operation or when something goes wrong or breaks.

All CAM machines should be equipped with safety switches connected to the machines safety shields so that when any of the safety shields is opened to gain access to the machine's working parts or to change or adjust the tool or work-piece the safety switches will disable and turn off the electronics and machine power so that the machine cannot move in any way and hurt anyone or do any kind of damage.

Your CAM machine's electronics should be equipped with a large red emergency power cut off "mushroom" shaped button, or similar large push switch, that will turn off the power to your automated machine and stop all motion of its parts in an emergency. This "panic" switch should be located within reach of the machine so that the operator can push the emergency power cut off switch if he gets hurt or needs to stop the machine from damaging itself or the part being made. This type of switch can be wired to a "latching" relay in such a way that once the button is pushed the power stays off until a key switch is turned to "reset" the power.

Some CAM machine's have a computer that lets the machine operator enter the commands to generate the tool path file for manufacturing the part directly, by various methods, while standing at the machine looking at the machine's computer's screen. Tool path files can also sometimes be generated elsewhere, such as in the drafting room or at home, and then taken to the CAM machine on a disk or transmitted to the CAM machine over a computer network. My CAM programs allow for both methods of working, you can teach the machine what to do on the computer connected to the machine, or you can create the tool path while sitting at a computer elsewhere. My CAD and CAM programs also allow the creation of the tool path to be done automatically or semiautomatically from scanning in the CAM machine, from a scanned or imported image file, or from running a macro program that computes the motions.

Since CAM machines can be operated to make just one, or a few, movements at at time, or operated automatically for hours or days at a time, there can be a use continuum between manual, semi-manual, semi-automatic, and fully automatic operation of the machine tool. In manual operation of the machine tool through the CAM system the CAM system mostly acts as a DRO to display the tool position relative to the work-piece. In semi-manual operation of the CAM machine the machine operator might enter the movements and feed rates for each movement or cut one at a time and let the computer act as a power feed. In semi-automatic operation of a CAM machine the machine operator might jog the tool to a point over where a hole or pocket is to be machined, then a "canned cycle" tool path file would be invoked to do the motions starting at the point jogged to. In fully automatic operation the CAM machine would be homed up to the home switches and the tool path would have all of the needed motions planed to complete the operations on the part without the machine operator having to do anything while the cutting proceeds. My CAM programs can be used for all of these operational methods, but caution is required when manual intervention is involved since it is easier to make mistakes when doing the motions manually.