Mesa Spinx1 on a Sherline mill

13 Jan 2016 01:52 - 13 Jan 2016 15:15 #68277 by comjon
Hardware and software integration and implementation guide for vocational to implement a cost effective method to modernize Sherline mills and lathes with spindle motor control via ‘S’ commands in CNC code.

Part I

For those readers looking to get started in the details of upgrading, begin at Part II. Others may find the introduction below helpful.

Forbes publication “Why We Desperately Need to Bring back Vocational Training in Schools”, September, 2015, summarizes the dollars and sense of returning to high school training in manufacturing. Optimism for manufacturing’s rebirth in the U.S. include: 1) cost competitiveness in U.S. wages 2) cheap domestic energy and 3) emerging technologies. This document focuses on the cultural transformation, emerging technologies, and a sample project serving as one solution to renewing vocational training.

Rebuilding vocational education in the U.S. requires a shift away from the consumption mentality to one of production, garage experimentation, math mindedness, and “on your feet” thinking from learning to application. It is not lack of awareness from business, industry, and education dragging on the momentum towards advanced manufacturing. What is needed is embedding tolerance for unrewarded effort and failure throughout our schools and communities, effort often labeled wasteful by the “bottom line” mindset. The dawn of the industrial internet calls our corporate leaders to embrace and manage risk by further lowering the boundaries of access for ideas and effort to flourish in manufacturing. Open source software projects are proof of this, notably the LinuxCNC initiative.

Vocational training can be risky and expensive, and industry requires considerable evaluation of the return on investment given the cost of infrastructure. An advanced CNC machining center easily costs a quarter million dollars, and the prohibitive matching cost of training diverts students from investing their time and borrowing for student loans. The perception that manufacturing is a risky venture seems to follow suit.

The pace of change adds to the complexity of implementing the most current technology into a profitable production process. It is no surprise hesitation is in order before signing the check to pay for training and equipment that finds obsolescence in a few years.

However, the rise of the Maker and Hackaday community of shared information is evidence that curiousity wins, aversion be damned. It begins in the garage; support on both the human and technical level provides the groundswell toward successfully renewing the apprentice culture in U.S. vocations.

Part II

At the LinuxCNC site you will find documentation to offer an open source solution to a stubborn problem plaguing entry level CNC training, advanced machining functionality in a cost effective solution. Critical to machining metals is control of the cutting tool determined by the properties of the type of material being worked. The substantial footprint of older, well manufactured milling and lathing equipment within reach of the novice through technical institutes makes upfitting feasible to both contain the cost of education and provide and initial and immediate hands on challenging project.

This document addresses replacing manual rheostat speed control found on Spectralight and Light Machines machining centers with standard Sherline equipment. The goal is replacing the rheostat with Mesa’s Spinx1 spindle control card, enabling command of the spindle’s revolutions per minute (rpms) with Gcode ‘S’ commands.

Spindle control in this example requires a second parallel port card. The first parallel port card is dedicated to four servo motors, three for the x, y, and z axes, and one for rotary table A axis. Other pins on the first parallel port card are reserved for future servo motor functionality.

The LinuxCNC Stepconf wizard leads the user through setting up a second parallel port, and the user may find the output of the standard 3 axis Sherline Stepconf .ini and .hal files included in the LinuxCNC software installation, which should provide basic functionality to standard Sherline equipment, helpful for comparative purposes to the downloadable hal and ini files with customized spindle control.

A minimum of three wires from the second parallel port to the Spinx1 will be required to properly send spindle direction, on/off, and PWM signal and ground between the LinuxCNC PC and the Spinx1. The Stepconf wizard suggests which parallel port pins to assign; pins 14, 16, and 17 are defaults. Choose any parallel pin 18 through 25 as your ground pin.

It is assumed the user has some knowledge of or should read and learn the basics of machining, programming and electrical concepts. This project should not be approached as “baking soda and vinegar” edutainment; you will be working with potentially lethal voltages, high velocities, and novel vocabulary which will require patience but challenge you in your successes. A line by line analysis of the customized hal and ini files is outside the scope of this document; check the LinuxCNC site for a “how-to” on LinuxCNC build and configuration files.

You absolutely must determine the correct voltage and polarity of the power you supply to the Spinx1. DO NOT trust the “wall wart” manufacturer’s labels. You will need a multimeter and basic knowledge of it’s use. Terminal block 1 can be identified through the PWM, ENA, DIR, and +5v labels, requires a 5 volt and a minimum 300 milliamps. Terminal block 2 is identifiable through the SP+, SPV, and SP- labels and may require 3.3 volts. Download the Spinx1 manual and read thoroughly to determine needs specific to your spindle motor. The spindle motor tested in this solution is a Hill House .2 horsepower, standard on older Sherline equipment.

If implementing this solution on a Light Machines or Spectralight center, you should verify the type of board wired to the rheostat and spindle motor, which will require cautious location, access and modification of this board. The Minarik 31002A is common to many Light Machines centers, and is the board documented in this solution.

Emergency stop was not tested in this solution; F1 on the keyboard provides emergency stop. Once the Spinx1 was correctly wired, energizing the 110v circuit sends a short pulse to the motor turning the spindle briefly before the Spinx1 board modulates the circuit. This short pulse to the spindle at PC boot and motor energize serves as a green light that the equipment is in good working order; be cautious that the spindle is free to turn safely prior to powering up your equipment.

Tinker, be patient, and think through what you are trying to accomplish. Share your successes on the LinuxCNC forum and join the maker community.
Last edit: 13 Jan 2016 15:15 by comjon. Reason: Citation Editing

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21 Apr 2022 03:53 - 02 May 2022 01:43 #240778 by garrettmin
Last edit: 02 May 2022 01:43 by garrettmin.

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