Composite Filament Winding Machine P09226

System Design Review

Christofer BraytonShijo George

Alex SandyTiago Santos

Daniel Weimann

Background

Why composite tubing?

High Strength Light WeightHigh creep and fatigue performanceChemical and corrosion resistance

Filament Winding

• The process by which a continuous strand of impregnated fibers is wound onto a mandrel with specific fibers’ orientation which is controlled by computer.

• Once resin has cured, mandrel is removed

RIT First Generation Filament Winding Machine

Capabilities

•Produce tubes of limited dimensions•Simple to operate•Maintain tension every time•Limited range of orientation angles•Able to be expanded upon

Primary Goals

•Learning Experience–New technology to RIT and students involved

–Create simple but bulletproof machine

Relative Speeds

Motors

Steppero Lower RPM rangeo Cheapero Simple

o Count steps to proper length

o DC

Servo

Two motors will drive the mandrel and feed eye individually. This will allow for variability in degree selection and higher ability to control position.

o “Built in” sensorso Easier to control if DCo Look into

o Retrofit kitso CNC upgrade kits

Motor Selection

AC vs. DC

Motors

Names Type Advantages Disadvantages Typical

Application

Induction

(Shaded Pole)

AC Least expensive, Long Life,

High power

Low starting torque Fans

Induction (split-

phase cap)

AC High power, high starting

torque

Rotation slips from

frequency

Appliances

Synchronous AC Rotation in-sync w/ freq,

Long life (alternator)

More expensive Clocks

Stepper DC Precision positioning, High

holding torque

Requires a controller Positioning in

printer

Brushless DC Long lifespan, Low

maintenance, High

efficiency

High initial cost, Requires

a controller

Hard drives,

CD/DVD players

Brushed DC Low initial cost, Simple

speed & torque control

High maintenance

(brushes), Expensive

Treadmill exercisers

Stepper vs. Servo Motor Stepper - brushless, synchronous electric motor that can divide a full rotation into a large number of steps. Acts as the bridge between digital information and incremental mechanical displacement. Used whenever controlled movement is required such as rotation angle, speed, position, and synchronism. Some applications are printers, plotters, hard disk drives, medical equipment, fax machines, automotive, etc. Advantages: -Rotation angle of motor is proportional to input pulse -Motor has full torque at standstill -Precise positioning -Excellent torque at low speeds -Excellent response to starting/stopping/reversing -High degree of reliability since no brushes (high lifetime) -No feedback required (open loop system) which eliminates need for expensive feedback devices such as optical encoders. Your position is known simply by keeping track of the input step pulses. -Wide range of rotational speeds can be realized as the speed is proportional to the frequency of the input pulses.

Disadvantages: -Resonances can occur if not properly controlled -Not easy to operate at high speeds Types: 1.) Variable Reluctance (VR) - Consists of a soft iron multi-toothed rotor and a wound stator. Poles become magnetized when windings are energized w/ DC current and therefore rotation occurs when the rotor teeth are attracted to the poles. 2.) Permanent Magnet (PM) - Low cost & low resolution type motor with typical step angles of 7.5 to 15 degrees (48 to 24 steps/revolution). The motor obviously consists of permanent magnets and is magnetized w/ alternating north & south poles situated in a straight line parallel to the rotor shaft. These poles provide an increased magnetic flux intensity & therefore it exhibits improved torque characteristics. 3.) Hybrid (HB) - Most expensive, but provides better performance with respect to step resolution, torque, and speed. Typical angles range from 3.6 to 0.9 degrees (100 to 400 steps per resolution). Combines aspects of VR and PM motor. Torque Calculation: H = (N X i) / l where: N=# of winding turns i=current H=Magnetic field intensity l=Magnetic flux path length Step angle calculation: Step angle = 360 / (Nph x Ph) where: Nph= # of equivalent poles per phase or # of rotor poles Ph = # of phases N = total # of poles for all phases together Displacement angle calculation: X = (Z / 2*pi) x sin( Ta / Th) where: Z = rotor tooth pitch Ta = Load torque Th = Motors rated holding torque X = displacement angle Step position error (non-cumulative) Step position error = measured step angle - theoretical angle Positional error positional error = difference of the max and min Information needed when selecting size of stepper: -Operating speed in steps/second -Torque in oz-in

Information needed when selecting size of stepper: -Operating speed in steps/second -Torque in oz-in T = F*r where: F = Force r = radius -Load inertia in lb-in^2 I = (W*r^2)/(2) for disk I = ((W*r^2)/(2)) (r1^2 + r2^2) for cylinder where: W = Weight in lbs r = radius of solid cylinder r1 = inner radius of hollow cylinder r2 = outer radius of hollow cylinder -Required step angle -Time to accelerate in ms -Time to decelerate in ms -Type of drive to be used -Size and weight considerations Servo - Can be AC or DC and usually is comprised of the drive section and the resolver/encoder. Much smoother in motion than a stepper and will have higher resolution for position control, but yet it is much more expensive. Electrical inputs determine the position of the armature of the motor. They are used in robotics and radio controlled cars, airplanes, and boats. Requires a control loop feedback of some kind. Advantages: -High intermittent torque -High torque to inertia ratio -High speeds -Works well for velocity control -Available in all sizes -Quiet -Can operate at zero speed and retain sufficient torque to hold a load in position -Ability to operate at very low speeds for long periods of time w/o overheating Disadvantages: -Higher cost -Feedback is required (Closed loop system) -Requires tuning of control loop parameters -More maintenance due to brushes if DC

Controllers

PLCo Programmable Logic Boardo Simpleo Basic Inputs/Outputso i.e., for Stepper

o Counts # of pulses

Microcontroller

To control position and speed of mandrel and feed eye relative to one another through motor control.

o More dynamico RIT availability

o EE Microcontroller classo CAST, bldg. 82

o Software?