evaluation of a low-cost material extrusion printer for ... · printer cost especially sensitive...

Evaluation of a Low-Cost Material Extrusion Printer for Investment Casting Applications

Tom Mueller

Mueller Additive Manufacturing Solutions

Mueller AMS

3D Printed Investment Casting Patterns

◼ 3D Systems introduced the QuickCast build

style 28 years ago

◼ Since then

◼ Several new technologies introduced

◼ Use of printed patterns for prototype

investment castings has become standard

◼ Used for very low volume production

◼ Enables investment casting for complex

geometries that can’t be molded

◼ One of most successful AM applications

◼ 4 Pattern printing technologies

dominate

ProX 800

QuickCast

Pro800X

SLS Castform

sPro 60

sPro 60

Printed Wax

Pro800X

3600 CPX

Projet

3600

PMMA

Pro800X

sPro 60

VX 1000

VX1000

Projet

3600

These 4 technologies

account for more than 98%

of printed patterns used in

North America

Study comparing these technologies in 2016

Pro800X

sPro 60

New Pattern Printing Technology?

◼ Some foundries experimenting with

inexpensive material extrusion printers

to print patterns

◼ Also known as Fused Deposition

Modeling (FDM)

◼ Several manufacturers and models

◼ Low end industrial printers

Could it be viable for pattern printing?

Investigation

◼ Manufacturer asked me to

evaluate their printer for IC

pattern printing applications

◼ Used Ultimaker s5 printer

◼ Used Polycast filament from

Polymaker

◼ Worked with Wisconsin

Precision Casting

◼ Evaluated its use in pattern

printing applications

Printed Patterns

◼ Hollow build style◼ Minimize build material

◼ Increase print speed

◼ Allow pattern to collapse as it expands

with heat in the autoclave

◼ A variety of infill settings are

available

◼ After testing, WPCC selected

◼ 10% triangular infill

◼ 0.2 mm skin thickness

What is Important for Investment Casting?

How big of a

part can it

build?


• Build Envelope

CriteriaWill the patterns be accurate enough to make a good casting?


• Build Envelope

• Accuracy

CriteriaWill the pattern be smooth enough to make a good casting?


• Build Envelope

• Accuracy

• Surface Roughness

CriteriaWill the printer be fast enough to create patterns when I need them?


• Build Envelope

• Accuracy


• Print Speed

CriteriaCan I afford to buy the printer?


• Build Envelope

• Accuracy


• Print Speed

• System Cost

CriteriaWill it cost too much to print the patterns?


• Build Envelope

• Accuracy


• Print Speed

• System Cost

• Pattern Cost

CriteriaWill the patterns be difficult to cast?


• Build Envelope

• Accuracy


• Print Speed

• System Cost

• Pattern Cost

• Casting Difficulty

Criteria

Printer Performance

Operating Cost

Casting Performance

Evaluation Criteria

Build Envelope

Accuracy

Surface Roughness

Build Speed

System Cost

Pattern Cost

Casting Difficulty

Printer

Performance

Operating

Cost

Casting

Performance

Build Envelope

Metric Imperial

Dimensions 330x240x300 mm 13x9.5x11.8 in

Volume 23.76 liters 1450 in3

Wisconsin Precision claims

that the s5 envelope will

accommodate approximately

70% of the castings they

produce.

How Does This Compare to Other Pattern Printers?

Evaluation Criteria

Build Envelope

Accuracy

Surface Roughness

Build Speed

System Cost

Pattern Cost

Casting Difficulty

Printer

Performance

Operating

Cost

Casting

Performance

Accuracy

• Accuracy in AM is complex

• Varies with build orientation

• Affected by layer thickness

• Little accuracy data exists

• Wisconsin Precision claimed it

was adequate for the castings

they produce

• Requirements vary with

application

• Decided to do a quick check

• Worked with University of

Northern Iowa

Quantifying Accuracy

◼ Proposed test artifact

◼ 9 stacked cubes

◼ A hole in each face of each

cube

◼ 3 faces

◼ 3 faces

◼ 6 linear dimensions per face -

outside

◼ 6 diameters per face – inside

◼ 36 dimensions per part

◼ 12 in each coordinate

directions

◼ 18 inside

◼ 18 outside

◼ Measurements done by

University of Northern Iowa at the

Metal Casting Center

A

B

C

X

Y

Z

1

2

3

4

5

6

Accuracy Measurements

Nominal PMMA Wax SLA Ultimaker PMMA Wax SLA Ultimaker PMMA Wax SLA Ultimaker

X (Y-Z plane) A 35.56 0.374 0.738 0.179 (0.421) 0.374 0.738 0.179 0.421 0.011 0.021 0.005 0.012

B 71.12 0.838 0.785 0.235 (0.167) 0.838 0.785 0.235 0.167 0.012 0.011 0.003 0.002

C 106.68 1.192 0.616 (0.031) 0.051 1.192 0.616 0.031 0.051 0.011 0.006 0.000 0.000

X 35.56 (0.001) (0.273) (0.485) 0.184 0.001 0.273 0.485 0.184 0.000 0.008 0.014 0.005

Y 71.12 0.280 0.055 (0.618) 0.330 0.280 0.055 0.618 0.330 0.004 0.001 0.009 0.005

Z 106.68 0.583 0.022 (0.702) 0.243 0.583 0.022 0.702 0.243 0.005 0.000 0.007 0.002

1 12.7 (0.080) 0.433 0.132 0.313 0.080 0.433 0.132 0.313 0.006 0.034 0.010 0.025

2 19.05 0.149 0.019 0.089 0.146 0.149 0.019 0.089 0.146 0.008 0.001 0.005 0.008

3 19.05 0.177 (0.085) 0.018 0.143 0.177 0.085 0.018 0.143 0.009 0.004 0.001 0.007

4 25.4 0.352 (0.261) (0.085) 0.081 0.352 0.261 0.085 0.081 0.014 0.010 0.003 0.003

5 25.4 0.163 (0.465) (0.066) 0.149 0.163 0.465 0.066 0.149 0.006 0.018 0.003 0.006

6 25.4 0.132 (0.166) (0.029) 0.172 0.132 0.166 0.029 0.172 0.005 0.007 0.001 0.007

Y (X-Z plane) A 35.56 0.428 0.353 0.424 (0.215) 0.428 0.353 0.424 0.215 0.012 0.010 0.012 0.006

B 71.12 0.669 0.442 0.117 (0.140) 0.669 0.442 0.117 0.140 0.009 0.006 0.002 0.002

C 106.68 0.942 0.489 (0.258) (0.043) 0.942 0.489 0.258 0.043 0.009 0.005 0.002 0.000

X 35.56 (0.273) 0.221 (0.449) 0.064 0.273 0.221 0.449 0.064 0.008 0.006 0.013 0.002 Y 71.12 0.273 0.542 (0.536) 0.683 0.273 0.542 0.536 0.683 0.004 0.008 0.008 0.010

Z 106.68 0.560 0.439 (0.880) 0.298 0.560 0.439 0.880 0.298 0.005 0.004 0.008 0.003

1 25.4 0.224 (0.382) 0.004 (0.167) 0.224 0.382 0.004 0.167 0.009 0.015 0.000 0.007

2 19.05 0.216 (0.333) (0.047) 0.065 0.216 0.333 0.047 0.065 0.011 0.018 0.002 0.003

3 25.4 0.157 (0.228) 0.006 (0.247) 0.157 0.228 0.006 0.247 0.006 0.009 0.000 0.010

4 12.7 0.375 (0.006) 0.274 0.041 0.375 0.006 0.274 0.041 0.030 0.000 0.022 0.003

5 25.4 0.188 (0.241) 0.141 0.118 0.188 0.241 0.141 0.118 0.007 0.009 0.006 0.005

6 19.05 0.212 (0.169) 0.000 0.114 0.212 0.169 0.000 0.114 0.011 0.009 0.000 0.006

Z (X-Y plane) A 35.56 0.250 0.762 0.424 0.266 0.250 0.762 0.424 0.266 0.007 0.021 0.012 0.007

B 71.12 0.783 0.520 0.281 0.223 0.783 0.520 0.281 0.223 0.011 0.007 0.004 0.003

C 106.68 1.168 0.550 0.273 0.084 1.168 0.550 0.273 0.084 0.011 0.005 0.003 0.001

X 35.56 0.371 0.499 (0.439) (0.209) 0.371 0.499 0.439 0.209 0.010 0.014 0.012 0.006

Y 71.12 0.854 0.511 (0.523) 0.014 0.854 0.511 0.523 0.014 0.012 0.007 0.007 0.000

Z 106.68 1.295 0.648 (0.626) (0.013) 1.295 0.648 0.626 0.013 0.012 0.006 0.006 0.000

1 25.4 0.361 (0.328) (0.321) 0.061 0.361 0.328 0.321 0.061 0.014 0.013 0.013 0.002

2 25.4 0.303 (0.339) (0.236) 0.209 0.303 0.339 0.236 0.209 0.012 0.013 0.009 0.008

3 19.05 0.106 (0.472) (0.185) 0.089 0.106 0.472 0.185 0.089 0.006 0.025 0.010 0.005

4 25.4 0.361 (0.194) (0.151) 0.056 0.361 0.194 0.151 0.056 0.014 0.008 0.006 0.002

5 12.7 0.104 (0.327) (0.078) 0.118 0.104 0.327 0.078 0.118 0.008 0.026 0.006 0.009

6 19.05 0.080 (0.276) (0.363) 0.158 0.080 0.276 0.363 0.158 0.004 0.014 0.019 0.008

Error (nomial-actual) Absolute Value of Error Absolute Value of Error

Error in mm Error in Percent of Nominal

CMM Measurements of the 36

dimensions by University of

Northern Iowa

2 Voxeljet artifacts

2 SLA artifacts

2 Printed wax artifacts

1 Ultimaker artifact

UNI

WPCC

Nominal PMMA Wax SLA Ultimaker PMMA Wax SLA Ultimaker PMMA Wax SLA Ultimaker

X (Y-Z plane) A 35.56 0.374 0.738 0.179 (0.421) 0.374 0.738 0.179 0.421 0.011 0.021 0.005 0.012

B 71.12 0.838 0.785 0.235 (0.167) 0.838 0.785 0.235 0.167 0.012 0.011 0.003 0.002

C 106.68 1.192 0.616 (0.031) 0.051 1.192 0.616 0.031 0.051 0.011 0.006 0.000 0.000

X 35.56 (0.001) (0.273) (0.485) 0.184 0.001 0.273 0.485 0.184 0.000 0.008 0.014 0.005

Y 71.12 0.280 0.055 (0.618) 0.330 0.280 0.055 0.618 0.330 0.004 0.001 0.009 0.005

Z 106.68 0.583 0.022 (0.702) 0.243 0.583 0.022 0.702 0.243 0.005 0.000 0.007 0.002

1 12.7 (0.080) 0.433 0.132 0.313 0.080 0.433 0.132 0.313 0.006 0.034 0.010 0.025

2 19.05 0.149 0.019 0.089 0.146 0.149 0.019 0.089 0.146 0.008 0.001 0.005 0.008

3 19.05 0.177 (0.085) 0.018 0.143 0.177 0.085 0.018 0.143 0.009 0.004 0.001 0.007

4 25.4 0.352 (0.261) (0.085) 0.081 0.352 0.261 0.085 0.081 0.014 0.010 0.003 0.003

5 25.4 0.163 (0.465) (0.066) 0.149 0.163 0.465 0.066 0.149 0.006 0.018 0.003 0.006

6 25.4 0.132 (0.166) (0.029) 0.172 0.132 0.166 0.029 0.172 0.005 0.007 0.001 0.007

Y (X-Z plane) A 35.56 0.428 0.353 0.424 (0.215) 0.428 0.353 0.424 0.215 0.012 0.010 0.012 0.006

B 71.12 0.669 0.442 0.117 (0.140) 0.669 0.442 0.117 0.140 0.009 0.006 0.002 0.002

C 106.68 0.942 0.489 (0.258) (0.043) 0.942 0.489 0.258 0.043 0.009 0.005 0.002 0.000

X 35.56 (0.273) 0.221 (0.449) 0.064 0.273 0.221 0.449 0.064 0.008 0.006 0.013 0.002 Y 71.12 0.273 0.542 (0.536) 0.683 0.273 0.542 0.536 0.683 0.004 0.008 0.008 0.010

Z 106.68 0.560 0.439 (0.880) 0.298 0.560 0.439 0.880 0.298 0.005 0.004 0.008 0.003

1 25.4 0.224 (0.382) 0.004 (0.167) 0.224 0.382 0.004 0.167 0.009 0.015 0.000 0.007

2 19.05 0.216 (0.333) (0.047) 0.065 0.216 0.333 0.047 0.065 0.011 0.018 0.002 0.003

3 25.4 0.157 (0.228) 0.006 (0.247) 0.157 0.228 0.006 0.247 0.006 0.009 0.000 0.010

4 12.7 0.375 (0.006) 0.274 0.041 0.375 0.006 0.274 0.041 0.030 0.000 0.022 0.003

5 25.4 0.188 (0.241) 0.141 0.118 0.188 0.241 0.141 0.118 0.007 0.009 0.006 0.005

6 19.05 0.212 (0.169) 0.000 0.114 0.212 0.169 0.000 0.114 0.011 0.009 0.000 0.006

Z (X-Y plane) A 35.56 0.250 0.762 0.424 0.266 0.250 0.762 0.424 0.266 0.007 0.021 0.012 0.007

B 71.12 0.783 0.520 0.281 0.223 0.783 0.520 0.281 0.223 0.011 0.007 0.004 0.003

C 106.68 1.168 0.550 0.273 0.084 1.168 0.550 0.273 0.084 0.011 0.005 0.003 0.001

X 35.56 0.371 0.499 (0.439) (0.209) 0.371 0.499 0.439 0.209 0.010 0.014 0.012 0.006

Y 71.12 0.854 0.511 (0.523) 0.014 0.854 0.511 0.523 0.014 0.012 0.007 0.007 0.000

Z 106.68 1.295 0.648 (0.626) (0.013) 1.295 0.648 0.626 0.013 0.012 0.006 0.006 0.000

1 25.4 0.361 (0.328) (0.321) 0.061 0.361 0.328 0.321 0.061 0.014 0.013 0.013 0.002

2 25.4 0.303 (0.339) (0.236) 0.209 0.303 0.339 0.236 0.209 0.012 0.013 0.009 0.008

3 19.05 0.106 (0.472) (0.185) 0.089 0.106 0.472 0.185 0.089 0.006 0.025 0.010 0.005

4 25.4 0.361 (0.194) (0.151) 0.056 0.361 0.194 0.151 0.056 0.014 0.008 0.006 0.002

5 12.7 0.104 (0.327) (0.078) 0.118 0.104 0.327 0.078 0.118 0.008 0.026 0.006 0.009

6 19.05 0.080 (0.276) (0.363) 0.158 0.080 0.276 0.363 0.158 0.004 0.014 0.019 0.008

Error (nomial-actual) Absolute Value of Error Absolute Value of Error

Error in mm Error in Percent of Nominal

Accuracy Comparison

-

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.400

0.450

PMMA Wax SLA Ultimaker

Err

or, m

m

Average Error

Average of the Absolute

Value of 36 Measured Errors

(Nominal – Measured)

Accuracy Comparison

Results – Average of the Absolute Error (mm)

Voxeljet SLA Printed Wax Ultimaker

Average 0.413 0.366 0.270 0.169

Std.Dev. 0.750 0.562 0.495 0.291

Accuracy Comparison

◼ Very small sample

◼ Too small to draw valid

conclusions about the accuracy

of the s5 relative to the other

systems.

◼ However, we can conclude that

the accuracy of the s5 is

competitive relative to the other

systems.

Evaluation Criteria

Build Envelope

Accuracy

Surface Roughness

Build Speed

System Cost

Pattern Cost

Casting Difficulty

Printer

Performance

Operating

Cost

Casting

Performance

Surface Roughness

◼ Surface roughness of the casting can be no better than the roughness of the pattern

◼ Wisconsin Precision requirements are not stringent.

◼ Finishing process◼ Quick sanding to knock down

build lines

◼ Vapor polishing to smooth surfaces

Vapor Polishing

◼ An advantage of the Polycastmaterial is that it can be vapor polished

◼ Small polishing units are effective and inexpensive

◼ Polishing smooths the surface and seals it

◼ Wisconsin Precision claims that the surface finish is adequate for their purposes

Evaluation Criteria

Build Envelope

Accuracy

Surface Roughness

Build Speed

System Cost

Pattern Cost

Casting Difficulty

Printer

Performance

Operating

Cost

Casting

Performance

Build Speed

◼ Build speed varies with

◼ Part geometry

◼ Number of patterns being built

◼ Layer thickness

◼ A good measure is to average the

apparent build speed (ABS) for a

number of builds

◼ S5

◼ Averaged over 26 builds

◼ ABS = 2.14 in3/hr

Part

NumberPicture

Volume

(cubic inches)

Build Envelope in

inches (L x W x H)

Build time

10% infil

Build

Rate

1 82.77 6x6x8 14.78 5.60

ABS =Total Vol. of Patterns Built

Total Build Time

Average Build Rate, in3/hr

Evaluation Criteria

Build Envelope

Accuracy

Surface Roughness

Build Speed

System Cost

Pattern Cost

Casting Difficulty

Printer

Performance

Operating

Cost

Casting

Performance

Printer Cost

◼ Especially sensitive for foundries

◼ Castings from printed patterns ~2-5% of revenues

◼ Do they spend limited capital on something that only affects a small

portion of their revenues?

◼ Or should they spend it on a robot or software that will lower costs on

all their production?

◼ Used list prices

◼ Nobody pays list

◼ Average actual prices are very difficult to find

◼ Does not include

◼ Facility modifications necessary

◼ Associated equipment

Printer Cost

How to Compare Costs of Printer with Different Speeds?

Capacity Cost = Printer Cost

Build Rate

Capacity Cost

Evaluation Criteria

Build Envelope

Accuracy

Surface Roughness

Build Speed

System Cost

Pattern Cost

Casting Difficulty

Printer

Performance

Operating

Cost

Casting

Performance

Pattern

Cost

Material

Cost

Labor

Cost

Depreciation

Cost

Maintenance

Cost

Material Cost

Material

Cost

◼ Material Cost includes:

◼ Pattern Material

◼ Support Material

◼ Other consumables

◼ Use list prices

◼ Assume Support volume is 50% of

pattern volume on average

Material Cost

Depreciation Cost

Depreciation

Cost

◼ Assume straight line depreciation with

a 7-year life

◼ Monthly depreciation = purchase

price/84

◼ Assume monthly production is 320

hours

◼ 5 days per week

◼ 16 hours per day

◼ Depreciation per in3 = monthly

depreciation/monthly production

Monthly Production

Depreciation Cost

Maintenance

Cost

◼ Maintenance cost is hard

to determine

◼ Approximate by the cost of

the most expensive

maintenance contract

◼ Divide monthly

maintenance contract cost

by monthly production to

get cost per in3

Maintenance Cost

Total Cost, $/in3 Sum of Material, Depreciation and Maint. Costs

Build Cost vs. Build Speed

CPX3600

sPro60

ProX800

s5 8-s5

VX 1000

Build Cost vs. Build Speed

CPX3600

sPro60

ProX800

s5 10-s5

VX 1000

Multiple Low-Cost Printers?

ProX 800 10 – s5

Build Rate, in3/hr 21.06 21.4

Printer Cost, $ $550,000 $91,000

Pattern Cost, $/in3 $3.88 $0.77

Ratio

102%

17%

20%

Capacity after printer

failure

0% 90%

Evaluation Criteria

Build Envelope

Accuracy

Surface Roughness

Build Speed

System Cost

Pattern Cost

Casting Difficulty

Printer

Performance

Operating

Cost

Casting

Performance

The Investment Casting Process

Courtesy of Ruger

Investment Casting

X X

Casting Process Modifications for Printed Patterns

◼ Assembly

◼ Add vents to printed patterns

◼ De-Wax

◼ Open vents prior to autoclave

◼ Pattern burnout

◼ Lower oven temperature

◼ Oxygen addition to oven

◼ Enable airflow through shell

◼ Cool Shell after burnout

◼ Blow out/Rinse out ash

◼ Patch vents

Modifications to the Casting Process

Assembly

Shell

De-Wax

Preheat

Pour

Shell Removal

1 VentMult. Vents

Open Vent

Burnout

Clean/Patch

VoxeljetQuickCast Projet WaxCastForm

Clean Up Grind VentGrind Vents

Cool Down

Burnout

Clean

Cool Down

Burnout

Clean/Patch

Cool Down

Conventional PLA

Burnout

Clean/Patch

Cool Down

Vent

Grind Vent

Casting Difficulty – Easiest to Most Difficult

◼ Printed Wax

◼ Castform

◼ PLA

◼ PMMA

◼ QuickCast

Tie

Summary

Evaluation Criteria Results

Build Envelope Acceptable for many foundries

Accuracy Competitive

Surface Roughness Acceptable for many foundries

Build Speed Faster than printed wax

System Cost Lowest printer price and capacity cost

Pattern Cost Lowest pattern cost

Casting Difficulty Slightly easier than QuickCast

Conclusion

• They have competitive printer performance

• They are less expensive

• They have a lower capacity cost

• They have lower pattern costs

• They are easier to cast than QuickCast patterns

Low cost material extrusion printers like the Ultimaker

s5 printer running PolyCast filament are viable for

printing investment casting patterns because:

Wisconsin Precision

◼ Now have 3 s5 printers

◼ Have a large capacity vapor polishing

unit

◼ Significant reduction in pattern

purchases

◼ Considering printers with larger build

envelope

Implications

The availability of low-cost

pattern printers will result in:

◼ Increased foundry

purchase of printers

◼ Increased use of printed

patterns for production

Thanks to:

Wisconsin Precision Casting Corporation

Thank you!

Questions?

Tom Mueller

Mueller AMS

[email protected]

(224) 548-2191

evaluation of a low-cost material extrusion printer for ... · printer cost especially sensitive...

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