We have created a modified program for the Sherline CNC Rotary Table Controller to allow it to drive other rotary tables. If you already have a rotary table and wish to utilize our controller, send us an email. You will need to use the Sherline 23 frame stepper motor with 1/4" shaft and 120 oz/in of torque. We also need to know the worm gear ratio of your table. Currently we support 40:1, 60:1, 72:1, and 90:1 ratios. Others may be available on request. CLICK HERE to see our system mated to a six inch import rotary table.

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Mumford Micro Systems has developed a hand-held electronic controller to drive a small rotary table made by Sherline Products in Vista, California. This intelligent controller is used to automate repetitive machining and indexing operations on Sherline's CNC version of their 4" rotary table. The controller features a 16-button keypad for entering commands and parameters, and a 2-line by 16 character backlit LCD display. The table can be used for circular cutting operations on milling machines or for rotary indexing in a variety of situations. It can also be mounted to the headstock of a lathe to index for clock wheel cutting, eliminating the need for dedicated index plates. It is a self-contained computerized tool that needs no other CNC equipment to use, though it can interface to other CNC controllers if you have them.

The keypad on the controller allows the operator to enter parameters of operation. There are three primary modes:

• Division Mode
• Degrees Mode
• Program Mode

Division Mode
In the Division Mode, you can specify the number of divisions in which to divide one rotation of 360 degrees. For example, if you wish to index a clock gear with 36 teeth, you would enter "36". Then, every time you press the NXT button, the table will rotate 1/36th of a rotation. You can press PRV to step backwards 1/36th of a rotation. The table automatically takes up backlash, and you can program the amount of backlash correction. The LCD screen keeps track of the current position and tells you which step you're currently at.

Degrees Mode
In the Degrees Mode you can enter an explicit number of degrees to rotate. For example, you might enter "120.050" degrees. Then, every time you press the NXT button, the table will rotate 120.050 degrees. You can press PRV to step backwards 120.050 degrees and the table automatically takes up backlash. The LCD screen keeps track of the current position and tells you what the step size is and what position you're currently at.

Program Mode
The Program Mode allows you to enter up to 40 steps in each of two different programs. Each step specifies a number of degrees to move either clockwise or counterclockwise, the feed rate for that move, and whether or not to pause after execution of that program step. As you enter the program you can INSERT or DELETE steps if errors are made. After a program is entered, each press of the NXT button advances the table to the next program step. The LCD screen keeps track of the program sequence and tells you what the current program step and size are. Programs are retained even with power turned off until they are changed by the user.

Jog Mode
A separate button is provided as a Panic Stop and to put the controller in Jog Mode. This will instantly halt all motion and disengage the the stepper motor. There is a hand crank on the motor shaft, allowing the operator to turn the table by hand. The keypad can also be used to rotate the table clockwise or counterclockwise at the current feed rate or in very fine individual steps.

Specifications
The resolution of positioning is .0125 degrees. Each step is within .0064 degrees of the exact position requested. The motor has a holding torque of 110 oz/in and speeds as fast as 50 degrees per second can be acheived. Ramping is used to achieve the higher step rates, and a Setting Mode allows you to enter the ramp values. Power is provided by a 110 volt AC adaptor. The motor drive is a 24 volt, 2 amp current limiting chopper design with 32 step microstepping for smooth motion. It includes an interface connector for connections to other CNC controllers. The interfaces include step and direction input and sense and acknowledge protocol for remote operation of the program sequences.

Indexing a lathe headstock with the tool
Ray Bates, a clockmaker in Newfane, Vermont, has recently mounted one of the rotary indexers to the headstock of his South Bend lathe. He'll be using this setup for clock wheel cutting, eliminating the need for indexing plates. To see pictures of his setup, CLICK HERE.

To see a similar setup, with the CNC Rotary Table mounted to the headstock of a Sherline lathe, CLICK HERE.

Using Sherline controllers with CNC software on a PC
It's also possible to use the Sherline CNC controllers as step and direction motor drivers for CNC software. To read about this, CLICK HERE.

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Availability
The CNC Rotary Table is available directly from Mumford Micro Systems for a price of $725 plus shipping. The package includes:

• The Sherline 4" rotary table with stepper motor attached
• The Mumford electronic controller
• 110 volt AC adaptor
• Six foot motor cable to connect the rotary table to the controller

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Accessories you may wish to consider

3 Jaw Chuck, 2.5" O.D. Mounts to the center of the rotary table to hold workpieces. Part number 1041 --- $100	Tilting Angle Plate. You can bolt the rotary table to the angle plate and position it at any angle. Includes holdowns. Part number 3750 --- $110

WW collet holder. Mounts to the center of the rotary table to hold workpieces.

The Fagor 8040 and 8055 CNC units feature dual operating systems. One system provides icon key-based conversational programming while the other provides traditional programming using standard G codes. The conversational system helps less experienced operators create a CNC program for small-lot production or prototyping. The G-code system allows the expert operator to create optimized programs for large-run applications. For conversational programming, the user presses a key bearing an icon of the milling operation that calls up a picture of a sample part with entry boxes for appropriate axis coordinates, dimensions and conditions that define the operation. The user can then execute the created program or save it.

Able to handle workpiece diameters from 6-36 in., GS:H machines accept operator-entered workpiece and material parameters and GearSmart software calculates feeds and speeds. Products utilize Fanuc control, million-count encoders on all axes, servo-driven hob, and direct-drive linear axes. Pre-loaded ground ball screws provide consistent tooth spacing, and CNC provides data storage for hob life management, part definition, hob geometry, and process data.

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WARREN, OHIO–Drake Manufacturing offers a complete line of CNC Gear Hobbers that handle workpiece diameters from 6″ to 36″.

Quick changeovers and intelligent programming are key in today’s short run environment. Each Drake hobber is equipped with the latest Fanuc controls and the company’s proprietary GearSmart(TM) software configured specifically for customers’ parts. All the operator has to do is enter workpiece and material parameters into the menu driven screens and the software calculates feeds and speeds.

Drake makes all of its machine tools very easy to operate. “Our customers do not want machine tools, they want quality parts out their door,” said Jim Vosmik, Drake president. Our GearSmart(TM) programming guarantees “good parts out your door from day one.”

Precision hobbing is assured with CNC positioning control and superior rigidity of both cutter and work drives. Million-count encoders are used on all axes; the hob is servo-driven; linear axes are direct-driven.

Drake’s new GS:H machines use proven pre-loaded ground ball screws to provide excellent lead and index accuracy and consistent tooth spacing.

System software and servo motors control all movable axes (no change gears are used), so set-up is much simpler, changeover is faster and productive machine time is increased. The CNC provides data storage for hob life management as well as part definition, hob geometry and process data to expedite changeovers.

Optional GS:H systems include power helix, auto loading, hydraulic work clamping, high-speed hobbing, automatic stock dividing and thermal compensation.

Drake Manufacturing designs, builds and services state-of-the-art precision CNC grinding and gear hobbing machines that help maximize productivity, improve quality and reduce production costs for a wide variety of demanding applications.

EditCNC includes many powerful features designed purely for CNC programming and editing, as well as the basic features you’d expect from any editor of this quality, such as search & replace, multiple undo/redo, multiple open files, file size limited only by the capacity of your computer, etc. In addition, EditCNC includes many powerful features designed purely for CNC programming and editing. Use EditCNC as part of your arsenal of CNC programming tools.

Experienced programmers know that different types of jobs require different methods for the most efficient programs. Sometimes it’s your full blown CAD/CAM, sometimes MDI, and sometimes it’s an editor on your PC - or a combination. Most basic CNC programming can be done faster and easier just by writing the g-code. EditCNC makes that even easier.

Synopsis:
Fanuc Power Mate (Models D, F) has an option called “Workpiece Number Search”. Using this option, the PMC can initiate the execution of a specified part program. This is especially useful in cases where the Power Mate is used to control special purpose machines that produce a known set of components. Such applications are found in batch production factories.

How it Works:
To synchronize the PMC and CNC functions, there is a communication area in the Fanuc Power Mate where the PMC & CNC exchange signals. These are a set of bytes and there are two areas namely:

a) The “G” area - signals from the PMC to the CNC

b) The “F” area - signals from the CNC to the PMC

By selectively loading G009 with a value in the range 1-255, the CNC will execute a program between O001 to O255.

Synopsis:
For machining very large programs on a general purpose CNC, the internal part program memory may become a constraint. This is usually the case with CAD generated programs for Die milling where the program size may run into the range of 20-30Mb, which is far beyond the capacity of a standard Fanuc-0 control. To execute such programs the alternatives are:

a) Breakup the programs to smaller manageable chunks as per the memory capacity of the control and execute it one by one.

b) Use the DNCI function available with the control.

Option a) is cumbersome since a lot of pre-processing has to be done to break up the program and while machining, after execution of every chunk the part program memory must be cleared, a new chunk loaded and executed. This involves a lot of operator intervention and may result in serious accident if a chunk out of sequence is loaded. This is where the DNCI option can be a big advantage.

What is DNCI?
DNCI is an add-on to the AUTO mode of the CNC where instead of executing the part program from the memory of the CNC, it executes program blocks dynamically transferred to it through the RS232 port. This article explains how to set up the DNCI and successfully execute programs.