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Sherline Products 8700 Using And Installation Manual

Cnc rotary table and controller
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SHERLINE CNC Rotary Table
P/N 8700
Dimensions
Table diameter: 4.0" (102mm)
Table height: 2.0" (51mm)
CLICK HERE
to view a dimensioned drawing of the rotary table with stepper motor mounted, or see the
General Description
page on the CNC rotary table for performance specifications.
INSTALLING AND USING
THE SHERLINE CNC ROTARY TABLE AND CONTROLLER
By Bryan Mumford and Joe Martin
INTRODUCTION
Bryan Mumford and I are very proud of this product. It has taken Sherline twice the investment in both time and money
compared to what we originally planned for this project. This project would have been a lot easier if we built the $4000 product
that we are competing with. We have taken a very expensive product that has only been available to very successful professional
businesses and produced a self-contained unit that not only has the features of the expensive units, it is also simpler to use and
very affordable. In fact, it is so inexpensive, home hobbyists can now afford to own and use this equipment. It should also be
noted that we didn't copy anyone to accomplish this feat. My only disappointment was that I was unable to find a way to adapt
our existing rotary tables to a CNC unit. It just couldn't be done in a cost-effective manner because of the mechanical parts that

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  • Page 1 SHERLINE CNC Rotary Table P/N 8700 Dimensions Table diameter: 4.0" (102mm) Table height: 2.0" (51mm) CLICK HERE to view a dimensioned drawing of the rotary table with stepper motor mounted, or see the General Description page on the CNC rotary table for performance specifications.

  • Page 2: Positioning Accuracy

    couldn't be interchanged due to the way the rotary table is manufactured. Even though the computer is small, it is a very complex device that both computes and drives the stepper motor in microsteps. Like all electronic devices, the easier it is to operate, the harder it is to design and program. We believe the instructions are easy to read and shouldn't give you any problems, but if they do, please notify us at Sherline, and we will attempt to improve them.

  • Page 3: The "Settings" Mode

    Sherline rotary table. Though you can still crank the table by hand when in the jog mode or when the controller is turned off, the controller is designed to crank it for you in precise, measured steps. PRECAUTIONS REGARDING MANUAL MODE When hand cranking the handwheel in the manual mode, the stepper motor acts as a generator.

  • Page 4: Fast Setting

    When the screen displays: Settings Mode Press Enter Press the [ENTER] key. The screen will then display something similar to: Slow: 15 Enter a number* The number after the word SLOW is the minimum feed rate of the rotary table. This is the speed with which the table starts each movement.

  • Page 5: Moving The Table

    instructions); however, it cannot be totally eliminated. The controller supports electronic backlash correction to compensate for whatever actual backlash remains in the worm gear. It works in this way: Every time the table makes a motion in the "reverse" direction, it will overshoot the amount of travel by the backlash amount, and then move "forward" by the same amount. This takes up any backlash in the worm gear.

  • Page 6: General Specifications

    GENERAL SPECIFICATIONS • The resolution of positioning is ± .006 degrees. • The speed of rotation can be set from one degree per second to 50° per second. Note that the higher speeds do not have much power and should only be used for positioning the table quickly, not for cutting operations. •...
  • Page 7 When the number of divisions you want is displayed, press [ENTER]. For example, suppose you typed "030" for the number of divisions. After you hit the [ENTER] key, the LCD screen will display: Division # 1 Press Nxt or Prv This means that the table is at position one (of 30), and it is waiting for you to press the [NXT] or [PRV] keys.

  • Page 8: The "Program" Mode

    appear on the LCD screen where the cursor is blinking. To move the cursor left, press the [PRV] (Previous) key. To move the cursor right, press the [NXT] (Next) key or type any digit. You can also specify whether the table is to move clockwise or counterclockwise when you enter the number of degrees to move.

  • Page 9: Entering A New Program

    2) The direction of travel (clockwise or counterclockwise), 3) The feed rate for that move, and 4) Whether or not the table should wait for you to hit the [NXT] key after each block of information is completed. The program you enter will be remembered indefinitely (unless you change it), even if you turn the controller off. There is room for two separate programs of 40 blocks each.
  • Page 10 Block 1:1 Feed rate: 15 This means that the feed rate for this programmed block is 15 degrees per second. The number you enter will be the fastest rate the table will reach during a move. The SLOW rate (the rate it starts at each time) depends on what you entered for SLOW in the Settings Mode.
  • Page 11 Delete? You can now delete the current program block by hitting the [ENTER] key. The LCD screen will display something similar to: Block 1:5 Wait... After a few seconds the word "Wait..." will go away and the previous settings for that program block will have been removed and replaced by the settings for the next program block.

  • Page 12: Continuous Motion

    You can press the [STOP] key at any time to abort table motion and it will enter you into the Jog Mode. Remember that you will lose your place and have to manually move to your home position before running your program. RESTARTING THE PROGRAM After all of the steps in the program are completed, the program will stop and wait for you to hit the [NXT] key if you stored a "Pause"...
  • Page 13 In this mode the controller will wait for a low-going STEP command. As soon as it is found, the table will move .0125 degrees clockwise if the DIRECTION input is high. If the DIRECTION input is low, the table will move .0125 degrees counterclockwise. There are 28,800 steps in a full rotation of 360 degrees.

  • Page 14: Limit Switches

    initiated from either the keyboard or the remote switch.) LIMIT SWITCHES Although the use of limit switches would be unusual with rotary tables it is a feature that's built in for our CNC linear tables so we thought we would bring it to your attention. The Sherline Controller supports the use of limit switches to avoid running a cutter into a fixture or clamp.
  • Page 15 The following instructions are included to give you some further insight into the fine points of using a rotary table for machining operations. Sherline Products Inc. makes a wide variety of miniature machine tools, which now includes the CNC rotary table (P/N 8700).
  • Page 16 FIGURE 3--Rotary table mounted to a riser block (P/N 8710) FIGURE 4--Sherline's tilting angle table (P/N 3750) is designed to hold the rotary table and allows it to be tilted to any angle from 0° to 90°. The thickness of its base provides the same function as the riser block shown in Figure 3. Don't let the reasonable price mislead you into believing this is not a precision piece of equipment.
  • Page 17 When working with a rotary table, the term "backlash" must also be used. Backlash occurs in all rotary tables and exists between the worm and worm gear just as it does in a leadscrew, so it must be considered. In the case of this particular table it amounts to .2°...
  • Page 18 FIGURE 6--Cutter machining outside of part FIGURE 7--Cutter machining inside of part Figures 6 and 7 show the relation of cutter and part. Start considering what I refer to as CPR, which is where the center of the cutter is from the center of the rotary table. The next problem to be aware of is why the rotary table must be offset to cut segments.
  • Page 19 FIGURE 8--This example shows how easy it is to allow for the cutter diameter using trigonometry FIGURE 9--Offsetting the rotary table to cut segments Now we have the offsets calculated and the rotary table "indicated in" in relation to the spindle. We move the X-axis the amount of the offset, moving the table to the left.
  • Page 20 FIGURE 10--Drawing and calculations for cutter paths The rotary cuts are made with the X-axis in its proper position, and the table rotated counterclockwise. One of the really neat things in machining happens when using a rotary table to feed work into an end mill, and I believe it comes about because of the slow and precise feed that can be obtained.
  • Page 21 FIGURE 11--Completing the spokes of a wheel CUTTING GEARS WITH A CNC ROTARY TABLE I am going to leave it up to you to determine when you know enough about gears to try to produce one. One of the best sources for information on gears is Machinery's Handbook.

  • Page 22: Maintenance

    precise. Gears are usually produced by "hobbing". This method uses a cutter that is similar to a worm gear. The teeth are generated with both the cutter and the blank turning. In fact, the process looks just like a worm gear running. Methods like this produce perfectly shaped teeth that are perfectly spaced.
  • Page 23 A NOTE ON MOUNTING THE RIGHT ANGLE ATTACHMENT FIGURE 13--Right angle attachment On the side of the worm housing (see exploded view on next page) are four holes that are used to mount the optional right angle attach-ment, P/N 3701. They go all the way through the part. In order to keep dirt and chips from entering the worm housing, setscrews have been installed in the holes.
  • Page 24 Gear cutters may be purchased from large, industrial tool suppliers. One of the best known is Manhattan Supply Company in New York. They may be reached at (800) 645-7270 or you may go to their web site at www.mscdirect.com to order their catalog or CD-ROM.
  • Page 25 So, if my instructions seem somewhat redundant, please forgive me. I could be living on a 60-foot yacht in the South Pacific if I could recover the money in scrapped parts made by employees of mine who cut first and thought later! Joe Martin, President and owner Sherline Products Inc.
  • Page 26 PART NO. REQ. DESCRIPTION NUMBER 10930 3/8" Bearing 30560 10-32 T-nut 35580 Hold-down clamp 37090 Chuck adapter 37100 Rotary table base 37110 Rotary table top 37121 CNC rotary table worm housing (Not sold separately) 37131 CNC rotary table worm shaft (Not sold separately) 37122 CNC rotary table worm housing assembly 37123...
  • Page 27 37124 CNC rotary table coupling adapter 37150 Oiler 37160 Preload nut 37170 Lock pin 37200 10--32 x 3/8" button head socket head screw 37210 Hold-down tab 37220 6-32 x 1/4" button head socket head screw 40050 1-5/8" handwheel assembly 40330 10-32 x5/8"...
  • Page 28 No part of this web site, including the text, photos or illustrations, may be reproduced or transmitted in any other form or by any means (electronic, photocopying, recording or otherwise) for commercial use without the prior written permission of Sherline Products Inc.

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