CNC Engraving Machine

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CNC Engraving Machine
Dave Korim Tim Nonna Ian Peck Drew Moyer Elliot
Seguin Amy Manganello
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Engraving Machines

• Current Models have
• Precision linear shafts
• Spindle Motors up to 100,000 rpm
• Step resolutions as low as 0.004 mil
• Integrated dust removal system
• Cost 8,000 - 15,000

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Initial Concepts

• Design One
• Stationary Table
• (12 x 12 inch)
• 2-axis of motion
• Enclosed Base

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Initial Concepts

• Design Two
• Stationary Table (24 by 24 inch)
• 3-axis of motion
• Custom built vacuum table
• Enclosed Base

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Initial Concepts

• Design Three
• Movable Table
• 3-axis of motion
• Stock vacuum table
• Enclosed Base
• 12 x 12 inch working area

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Final Design
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Final Design

• Physical Size
• Table top unit 24 x 17 footprint
• Working Area- 12 x 16
• Performance
• 3 axis controlled movement
• Max translation speed
• of 0.5 in/s
• precision to 0.31 mil

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Final Design

• All parts come from 7 Sources
• McMaster Carr
• Screws, bolts, motor couples, Aluminum sheet
  stock
• Penn Engineering
• Stepper Motors
• Nook Industries
• Linear Ball Screws
• Systematic Automation
• Vacuum Table
• 80/20 Inc.
• Frame
• Euchner
• Limit Switches
• Machine Shop
• 4 mounting plates
• 1 motor mount

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Motor Selection

• Pittman Model 0220 Stepper Motor
• NEMA 23 size/mounting configuration
• 1.8/Step (200 Steps/rev)
• 2.5 rpm at max torque (30 oz-in)

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Ball Screw Selection

• Determined by Resolution and Accuracy
• Pitch of 0.125 per revolution
• 0.31 Mil Resolution
• Translational Speed at Max. Torque 19 in/min
• Ball Screw Force of over 20 lbf
• Nook Industries Preassembled Slide System
• Just add motor

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Milling specs

• Variable spindle speed
• Min. 10,000 rpm
• Max. 60,000 rpm

• 1/8 bit diameter
• 1/8 chuck
• Cost 295.00

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Bending Analysis
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• Area One
• Bending of 3 x 3 inch 80/20
• Analysis done with 80/20 bending program
• Area Two
• X-translation Slide Assembly
• Analysis done with CosmosWorks

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Bending Analysis

• Area One
• Load on cross-member approximately 10 pounds
• Analyzed at 20 pounds
• Deflection of 0.004mm
• No significant Deflection

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Bending Analysis

• Area Two
• Load on slides 3.8 pounds
• Analyzed at 6 pounds
• Deflection of 0.00092 inches not significant

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Cost Analysis

• 80/20 Structure and fasteners 410.00
• Translation Assemblies
• X-Trans ball screw 2087.00
• Y-Trans ball screw 2154.00
• Z-Trans ball screw 2674.00
• Motors
• 3 Stepper Motors (size 23) 327.00
• Milling Motor 295.00
• Other Parts
• Plate stock for machined parts 57.55
• Vacuum Table 350.00
• 3 Limit Switches 187.65
• 3 Helical Couplings 113.61

• Total Cost 8,600.00

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Cost Breakdown
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Advantages/Disadvantages

• Plus
• High Accuracy
• Less expensive than market
• Quality Construction
• Simple to build
• Small Size
• Frame can be used for multiple purposes

• Minus
• Lack of Floating Head
• 80/20 is expensive
• Still somewhat expensive

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Questions

• ?