AMB2022-03 Benchmark Measurements and Challenge Problems – PDF Copy

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AMB2022-03 Benchmark Measurements and Challenge Problems

Last updated on 5/26/2022

Modelers are invited to submit simulation results for any number of challenges they like before the 

deadline of 23:59 (ET) on July 15, 2022. Tabulated results using the challenge-specific templates are 

required for most challenge problems and simulation results may be submitted here. An informational 

webinar for AMB2022-03 will be held on May 5, 2022, from 13:15 – 14:15 Eastern Time. The webinar 

registration link is here. After the webinar is completed, links to the recorded presentations and to a 

FAQ page will be added to the AMB2022-03 description page. Additional information may become 

available later so updated versions of this document may be posted. Please check back occasionally. 

All evaluations of submitted modeling results will be conducted by the AM-Bench 2022 organizing 

committee. Award plaques will be awarded at the discretion of the organizing committee. Because 

some participants may not be able to share proprietary details of the modeling approaches used, we are 

not requiring such details. However, whenever possible we strongly encourage participants to include 

with their submissions a .pdf document describing the modeling approaches, physical parameters, and 

assumptions used for the submitted simulations.

Please note that the challenge problems reflect only a small part of the validation measurement data 

provided by AM Bench for each set of benchmarks. The Measurement Descriptions section, below, 

describes the full range of measurements conducted.

AMB2022-03: Single laser tracks using different processing conditions and 2D arrays of laser tracks 

(Pads) on solid plates of IN718. Detailed descriptions are found below, and simulation results may be 

submitted here. 

Challenges

● Track Solid Cooling Rate (CHAL-AMB2022-03-TSCR): Cooling rate immediately following 

complete solidification (below solidus) at the center of each track for all processing conditions.

● Track Liquid Cooling Rate (CHAL-AMB2022-03-TLCR): Liquid cooling rate immediately before 

start of solidification (above liquidus) at the center of each track for all processing conditions.

● Track Time Above Melt (CHAL-AMB2022-03-TTAM): Time above the midpoint between solidus 

and liquidus temperature (assumed to be 1 298 °C) for single laser-scanned tracks.

● Track Melt Pool Geometry (CHAL-AMB2022-03-TMPG): The laser track width and depth near the 

center of each track for all processing conditions.

● Pad Solid Cooling Rate (CHAL-AMB2022-03-PSCR): Cooling rate immediately following complete 

solidification (below solidus) at the center of each track for all processing conditions.

● Pad Time Above Melting (CHAL-AMB2022-03-PTAM): Time above the midpoint between solidus 

and liquidus temperature (assumed to be 1 298 °C) for specified locations of the X-Pads and YPads.
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● Pad Melt Pool Geometry (CHAL-AMB2022-03-PMPG): Laser track depth and geometrical 

measurements describing the overlapping laser tracks near the center and near the edge of both 

X-Pads and Y-Pads. 

1. Overview and Basic Objectives

2. Sample and Laser Processing

3. Measurement Descriptions

4. Benchmark Challenge Problems

5. Description and Links to Associated Data

6. References

Document Updates from original release Version 1.00

Version 1.01 – Created on 5/26/2022

• Errors in the CHAL-AMB2022-03-PMPG and CHAL-AMB2022-03-TMPG submission 

templates have been corrected. Links now point to these updated templates.

_____________________________________________________________________________________

1. Overview and Basic Objectives

The AMB2022-03 benchmarks explore a range of individual and overlapping melt pool behaviors using 

individual laser tracks and 2D arrays of laser tracks on solid metal IN718 plates. For the individual laser 

tracks, a range of laser parameters were used, with variations in laser power, speed, and spot diameter. 

In situ measurements include time-resolved laser coupling, location-specific liquid and solid cooling 

rates, and location specific time above melting. Ex situ measurements include 3D topography of the 

solidified laser tracks and cross-sectional geometry and microstructure measurements. For the 2D pads, 

scan patterns and timing match those used for the odd (X-Pads) and even layers (Y-Pads) of the 

AMB2022-01 3D builds. The same sets of in situ and ex situ measurements used for the single laser 

tracks were used for the laser pad studies.

2. Sample and Laser Processing

2.1 Plate preparation: 

Sample substrates were cut from a rolled and annealed IN718 sheet (given MaterialID AMB2022-718-

SH1, see Section 2.5). Material certificate for the as-received IN718 sheet is available here.

The following steps were taken to prepare the samples:

● 3.17 mm (1/8”) thick IN718 sheet was cut to produce 25.4 mm x 25.4 mm (1” x 1”) bare plates

● The bare plates were random-orientation polished with 320 grit SiC paper

● The bare plates were residual stress annealed in vacuum at 800 °C for 2 h. This anneal was in 

preparation for possible future synchrotron X-ray measurements of elastic strains produced by the 

laser tracks. 

● The bare plates were random-orientation polished again with 320 grit SiC paper. The typical 

resulting surface roughness was Ra = 5.8 μm.
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2.2 Laser processing parameters

All individual laser tracks and laser pads were produced using the NIST Additive Manufacturing 

Metrology Test Bed (AMMT) which is a NIST-designed and built laser-processing metrology platform. 

Detailed references to the AMMT design, controller, and various other research may be found here. The 

AMMT is also a fully functional laser powder bed fusion (LPBF) AM machine, with a continuous-wave 

(CW) ytterbium fiber (Yb:fiber) laser, with a central wavelength of 1070 nm, directed by fullycontrollable scanning galvanometer mirrors. The controlled laser scanning is synchronized to various 

measurement instrument triggering and data acquisition.

Figure 1: Example of bare plate samples with different laser scan patterns and orientations. Laser-scanned traces can also be 

seen which are used to align and orient samples after cutting.

Figure 1 shows examples of bare plate samples with different laser scan patterns and orientations. 

Samples were mounted 6 at a time within the AMMT on a custom holder shown in Figure 2. Unlike the 

2018 AM-Bench samples, which were held by pins with minimal contact (e.g., thermal conduction 

paths), the 2022 AMMT samples are directly mounted with full contact on the bottom to a stainless 

steel 304 (thermal conductivity and specific heat within 30 % of IN718) baseplate and held down by two 

flat head screws. Each sample also had a k-type thermocouple which contacts the center underside.

A time period of at least one minute passed between the laser scanning of each track or pad to reduce 

effects of residual heat buildup. Thermocouples integrated with the mounting plate contacting the 

backside of the samples are shown in Figure 2, and all tracks were scanned at a sample temperature of 

23.5 ± 1.0 °C. The temperature measured on the backside of the sample rose a total of < 0.7 °C for each 

pad scan, and the temperature rose < 0.1 °C after each line scan.

Single tracks X-pad Y-pad
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Figure 2: Left: Sample mounting cutouts within the AMMT standard build plate, including thermocouples. Right: Example of 

samples mounted within the AMMT holder, including a Y-pad and single-line tests.

2.2.1 Single laser track measurements with thermography

The baseline parameters are listed in Table 1, and the offset laser parameters for all seven parameter 

sets are listed in Table 2. Figure 3 shows the layout and numbering of single tracks on the substrates.

Table 1: AMMT laser processing conditions for single tracks scanned on bare IN718 substrates

Base laser processing conditions

Laser power 285 W

Laser speed 960 mm/s

Pad hatch spacing 110 μm

Laser spot size (gaussian) 67 μm

Laser energy distribution Rotationally-symmetric Gaussian

Single track scan direction +X

Single track length 10 mm

Inert gas Argon

Max. Oxygen level < 1 000 ppm

Gas flow speed (Z = 10 

mm)

4.3 m/s

Gas flow direction -Y

Chamber pressure 95 ± 5 kPa

Substrate and chamber 

temperature

23.5 ± 1 °C

Laser incidence angle 5 ± 0.5 °

Surface roughness (Ra) 5.8 μm
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Figure 3: Layout and numbering of the 21 tracks, consisting of 7 laser scanning parameter sets (or ‘case number’) and 3 repeats 

per parameter set.

Table 2: Offset laser parameters for AMB2022-03 individual laser track thermography measurements with varying 

laser power, spot size, and scan speed. Each case is repeated three times for a total of 21 laser scan tracks. 

Volumetric energy density based on 1σ laser beam size, VEDσ, is also provided.

Case 

Number

Laser Power 

[W]

Scan Speed 

[mm/s]

Spot size, 

D4σ [μm]

VEDσ = P/v/σ

2 

[J/mm3] VED/VEDbase

Baseline 0 285 960 67 1058 1.00

Change spot 1.1 285 960 49 1978 1.87

1.2 285 960 82 706 0.67

Change Speed 2.1 285 1200 67 847 0.80

2.2 285 800 67 1270 1.20

Change Power 3.1 325 960 67 1207 1.14

3.2 245 960 67 910 0.86

2.2.2 Laser pad measurements with thermography

The laser parameters used for the laser pad measurements are the same as those used as the baseline 

parameter set for the single laser track measurements described above (see Table 1 and Table 2). The 

scan patterns and speed match those used for the odd and even layers of the 2.5 mm thick legs of the 

AMB2022-01 bridge specimen. In other words, Y-Pad here matches the Y scan pattern for the odd layers 

of the 3D builds, and the X-Pad here matches the X scan pattern for the even layers. However, note that 

the spot size here is different from the 77 μm D4σ spot size used in the AMB2022-01 builds. The X-pad 

scans, shown in Figure 4, are the same as the 2.5 × 5 mm Leg 9 within the camera field of view. The scan 

order and timing are based on layer 26 from AMB2022-01 3D builds. 

Line 0_1

Line 0_2

Line 0_3

Line 1.1_1

Line 1.1_2

Line 1.1_3

Line 1.2_1

Line 1.2_2

Line 1.2_3

Line 2.1_1

Line 2.1_2

Line 2.1_3

Line 2.2_1

Line 2.2_2

Line 2.2_3

Line 3.1_1

Line 3.1_2

Line 3.1_3

Line 3.2_1

Line 3.2_2

Line 3.2_3

x

y
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Figure 4: Left: Laser scan position. Red indicates laser is 'on', blue indicates laser is 'off'. Right: Layout geometry of the two Xpads and alignment marks.

The Y-pad scans, shown in Figure 5, are the same as the 2.5 x 5 mm Leg 9 from the AMB2022-01 bridge 

structure (albeit with different laser spot size) within the camera field of view, and one additional line 

from the 5 x 5 mm Leg 10. The scan order and timing are based on layer 27 from the AMB2022-01 3D 

builds.

Figure 5: Left: Laser scan position. Red indicates laser is 'on', blue indicates laser is 'off'. Right: Layout geometry of the two Ypads and alignment marks.

2.2.3 Single laser track measurements with dynamic coupling

The baseline parameters are listed in Table 3, and the offset laser parameters for all seven parameter 

sets are listed in Table 4. Note that the laser spot size is different from 3D builds and single laser track 

and pad scans with thermography measurements.
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Table 3: AMMT laser processing conditions used for AMB2022-03 dynamic laser coupling measurements while scanning single 

tracks on IN718 bare metal substrates

Base laser processing conditions

Laser power 285 W

Laser speed 960 mm/s

Pad hatch spacing 110 μm

Laser spot size (gaussian) 110 μm

Laser energy distribution Rotationally-symmetric Gaussian

Single track scan direction +Y

Single track length 10 mm

Inert gas Argon

Max. Oxygen level < 1 000 ppm

Gas flow speed (Z = 3 mm) 2.3 m/s

Gas flow direction +X

Chamber pressure 101 ± 2 kPa

Substrate and chamber 

temperature

23.5 ± 1 °C

Laser incidence angle 8 ± 0.5 °

Surface roughness (Ra) 5.8 μm

Table 4: Offset laser parameters for AMB2022-03 individual laser track dynamic coupling measurements with varying laser 

power, spot size, and scan speed. Each case is repeated three times for a total of 21 laser scan tracks. Volumetric energy density 

based on 1σ laser beam size, VEDσ, is also provided.

Case 

Number

Laser Power 

[W]

Scan Speed 

[mm/s]

Spot size, 

D4σ [μm]

VEDσ = P/v/σ

2 

[J/mm3] VED/VEDbase

Baseline 0 285 960 110 393 1.00

Change spot 1.1 285 960 76 822 2.09

1.2 285 960 131 277 0.71

Change Speed 2.1 285 1200 110 314 0.80

2.2 285 800 110 471 1.20

Change Power 3.1 325 960 110 448 1.14

3.2 245 960 110 337 0.86

2.2.4 Laser pad measurements with dynamic coupling

The laser parameters used for the pad dynamic coupling measurements are the same as those used as 

the baseline parameter set for the single laser track measurements described above (see Table 3 and 

Table 4). The scan patterns match those used for the odd and even layers of the 2.5 mm thick legs of the 

AMB2022-01 bridge specimen. Thus, the Y-Pad matches the Y scan pattern for the odd layers. 

The Y-pad scans are the same as those used for the 2.5 x 5 mm Leg 9, but excludes the additional line 

shown in Figure 5. The scan order and timing are based on layer 27 from the AMB2022-01 3D builds.

2.3 Gas flow system
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Inert gas flow across the laser melting process is used to remove process byproducts (metal vapor, 

condensate, and ejecta) from the laser path, build area, and chamber windows. Previous studies have 

shown that ineffective gas flow interferes with laser delivery and may result in powder bed 

contamination (Ladewig et al. 2016, Deisenroth et al. 2021). The AMMT gas flow system incorporates a 

two inlet and one outlet system, as shown in Figure 6a. As shown by the orientation of the fabric tufts in 

Figure 6a, the inlet locations at the top and bottom of the process enclosure prevent the formation of a 

recirculation zone that would reduce the efficacy of byproduct transfer to the outlet. 

The total flow rate of argon through the build chamber was approximately 390 L/min. This flow rate and 

nozzle configuration results in spatial distributions of the gas flow speed in the Y and Z directions, which 

are approximately invariant in the X direction across the build area. The combined speed resulting from 

the Y and Z velocity components of the flow was measured by hot wire anemometry at several Y and Z 

locations at approximately X = 0 mm to characterize the flow across the build space. Details of the speed 

measurements are described in Weaver et al. 2021. As shown in Figure 6b, the gas speed at the single 

track and pad location (near X = 0 mm, Y = 30 mm) at Z = 10 mm is approximately 4.3 m/s, which is used 

as a representative gas flow speed value. 

Figure 6: (a) AMMT process enclosure gas flow direction distribution based on fabric tufts. The image is flipped horizontally for 

ease of visualization and approximate axis directions (not origin) are shown. (b) gas flow speed distributions at varying Y and Z 

positions at approximately X = 0 mm.

2.4 In Situ Monitoring Systems Half of the bare plate samples were laser processed with simultaneous 

high-speed in situ thermography, and half were processed using in situ laser coupling measurement. 

The thermography samples were later cross-sectioned for optical microscopy and SEM while the 

laser coupling samples were measured using laser confocal microscopy.

2.4.1 Thermography: Figure 7a shows a diagram of the staring imaging system used for in situ 

thermographic measurements and Figure 7b shows a photograph of the completed system. To 

the greatest extent possible, this system was designed to provide nearly identical layer scan 
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patterns, measurement methods, instruments, and gas flow conditions for the sets of 3D build 

benchmarks (AMB2022-01 and AMB2022-02) and the 2D laser pad benchmarks (AMB2022-03).

Figure 7: Staring imaging system used for in situ thermography on the AMMT, a) CAD model and b) photograph.

The properties of the camera used for the in-situ thermography measurements are given in Table 5.

Table 5: Camera properties for high-speed staring thermography camera in the AMMT

Sensor Type: Si-based CMOS

View Angle: ~82o

Wavelengths: 830 nm to 870 nm

Magnification 1×

Window Size (x by y): (640 by 304) pixels

iFoV (x by y) (20.4 by 20.8) μm/pixel 

FoV (x by y) 13.1 x 6.4 mm

Frame Rate Up to 30 000 frames/s

Integration Time 20 μs

Bit depth: 12-bit (4096 DL)

Calibrated Temperature Range: 1001 °C to 1389 °C 
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2.5 Specimen Naming Convention

The AMB2022-03 bare plates use the following naming convention:

AMB2022-718-SH1: MaterialID for the IN718 sheet used to make square laser targets

AMB2022-718-SH1-BP1: Bare plate #1, 3 x 7 single laser tracks, in situ thermography

AMB2022-718-SH1-BP2: Bare plate #2, 2 x 2.5 mm X-axis pads, in situ thermography

AMB2022-718-SH1-BP3: Bare plate #3, 2 x 2.5 mm Y-axis pads, in situ thermography

AMB2022-718-SH1-BP4: Bare plate #4, 3 x 7 single laser tracks, in situ dynamic laser coupling

AMB2022-718-SH1-BP5: Bare plate #5, 2 x 2.5 mm X-axis pads, in situ dynamic laser coupling

AMB2022-718-SH1-BP6: Bare plate #6, 2 x 2.5 mm Y-axis pads, in situ dynamic laser coupling.

After completion of the laser scans, the in situ thermography specimens were cross-sectioned as shown 

in Figure 8. The naming convention for the individual cut sections is also shown in this figure. 

Figure 8: Bare plate sample sectioning and naming convention. The positions of cross-sections listed on each part 

were determined after metallographic sample preparation using fiducial markings. Red arrows are shown for 

schematic purposes only and do not indicate measurements from these images.

3. Measurement Descriptions

The AMB2022-03 single track and pad benchmark measurements include in situ phenomena during the 

laser track and pad processing and ex situ characterization of the 3D surface topography and the laser 

track and pad cross-sectional geometry and microstructure. The measurement methods include:

In situ measurements during laser melting

● In situ thermography to measure the location-dependent cooling rates of the melt pool 

immediately preceding solidification (before the liquidus is reached) and the solid 

material immediately after solidification (after the solidus is reached)
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● In situ thermography to determine the time above melting (above the midpoint 

between the liquidus and solidus)

● In situ dynamic laser coupling (i.e., absorption) 

Ex situ measurements

● 2D cross-sections of the thermography specimens were measured using a combination 

of SEM and optical microscopy

● Laser confocal microscopy was used to measure the 3D surface topography of the laser 

coupling specimens

3.1 In Situ Time Above Melting 

Before interpreting thermographic data products, it must be noted that the metal AM process creates a 

challenging environment for thermography. The challenges generated by rapid melting of metals can 

include image attenuation and distortion, changes in the optical path distance, extraneous light sources, 

and more. Therefore, all model comparisons will be made to the apparent temperature distribution, 

including any and all measurement error induced by the laser-matter interaction. The measurement 

results used for comparison will be the average of three experimental repeats for each combination, or 

‘case’ listed in Table 1.

The temperature history of the pixels of the thermographic images were evaluated with a comparable 

approach to AM-Bench 2018. The temperature history of 30 adjacent pixels along the centerline of the 

melt path were evaluated and aligned by the rising edges. The thermal histories were then mildly 

smoothed and then averaged to produce a representative thermal history of the melt pool at steady 

state, which is illustrated in Figure 9. 

The temperature discontinuity that indicates solidification was identified and fit with a cubic polynomial 

curve in a range of approximately ±50 °C of the apparent inflection point. The location at which the 

second derivative of the curve fit reached zero was then identified as the inflection point. The time 

between the corresponding inflection temperature at front and rear of the melt pool is the time above 

melting (TAM).
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Figure 9: Illustration of a representative steady-state centerline melt pool temperature history, the temperature discontinuity at 

solidification, and measurement of the TAM.

3.2 In Situ Cooling Rates

The established inflection point is assumed to be the midpoint between the nominal solidus and liquidus 

temperatures of 1 260 °C and 1 336 °C, respectively. As illustrated in Figure 10, three distinct cooling 

rates (CRs) can be identified from this approach. The CRs are found by the slope of a linear fit of the 

temperature data between two reference temperatures: the liquid CR is taken from 1 400 °C to the 

liquidus, the transition CR is taken from the liquidus to the solidus, and the solid CR is taken from the 

solidus to 1 150 °C. 

Figure 10: Illustration of the temperature ranges and linear fits used to establish three distinct CRs.

3.3 In-situ Dynamic Laser Coupling

Additional measurements were performed on the AMMT to acquire dynamic laser energy coupling 

(i.e., time-resolved reflected laser power) using a reflectometer-based method described in 

Deisenroth et al. 2020, and producing similar results to the 2022 Asynchronous AM-Benchmark tests

(A-AMBench2022). This method utilizes a hemispherical reflectometer, which is calibrated to

measure the time-varying amount of laser power reflected from the laser processing area. These 

measurements were acquired for the same laser processing parameters (except for a different laser 

diameter) as the single tracks and vertical and horizontal pads measured via high-speed

thermography as described in Section 2.2. No challenge problems will be associated with these 

measurements; however, the results and data will be released in July 2022 for model comparisons.

3.4 2D Cross Sections 

Cross-sections were made perpendicular (within 2° perpendicular) to laser tracks and pads using a 

rubber bond alumina abrasive blade (0.762 mm thickness) on a high-speed precision saw. Samples 
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were metallographically prepared and etched with Aqua Regia. Micrographs of the melt-pools were 

taken with optical microscopy using bright field and dark field imaging.

Cross-section locations were determined from fiducial laser tracks. The fiducial laser tracks were 

measured on the top surface prior to cross-sectioning and on the side surface of metallographically 

prepared cross-sections. The cross-section locations are relative to the left side of single tracks and 

X-pads and the bottom side of Y-pads as shown in Figure 8. 

3.4.1 Optical microscopy

Melt-pool depth and width measurements were made on optical micrographs. These are 

schematically shown in Figure 11. Because there is no powder in these experiments, the melt-pool 

depths are defined from the plate’s top surface ignoring any humping of material above the starting 

surface. Depth measurements are perpendicular to the top surface and width measurements are 

parallel to the top surface. The depths, dt and dp, are always the largest distance, not necessarily in 

the center of the melt-pool. The pad overlap depth, do, is the greatest distance from the top surface 

to where melt pools intersect. The widths are always the widest distance, not necessarily at the top 

surface. The pad width, wp, is measured from the depth line, dp, to the widest point of the melt 

pool. The pad overlap width, wo, is the distance between the widest point of a melt pool and its 

succeeding melt pool (e.g., wo1is measured between track 1 and track 2). These points need not be 

in the same Z-plane.

Figure 11: Schematic definitions of melt pool cross-section measurements for single tracks and pads. Blue dots indicate 

measurement points. Pad scans start at track 1 and end at track ‘n’. Melt-pool shapes may vary based on process variables, and 

the schematic is nothing more than a simple illustration.

3.4.2 Scanning electron microscopy

Cross-sections were prepared by progressive polishing from 600 grit SiC paper down to 1 μm diamond 

suspension. Final surface preparation used vibro-polishing with 0.05 μm non-colloidal silica for 16 h. 

Samples were cleaned in an ultrasonic bath in three solutions: soap/water, water, and ethanol.

Imaging and data acquisition were performed using a JEOL Field Emission JSM7100† with the Oxford 

Symmetry S2 EBSD detector† with fore-scatter diodes and the Oxford Ultim Max EDS 100 mm2 silicon 
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drift detector. Oxford Aztec† software Ver 6.0 was used for EDS/EBSD analysis and to create large area 

maps. The SEM measurement conditions are listed in Table 6. 

Table 6: SEM settings used for the 2D cross-section measurements

SEM 

settings

20 kV 10 nA 70 deg tilt Working distance ~ 

25 mm

400 x magnification

Field of view = 300 

pixels x 226 pixels 

(0.3 mm x 0.23 

mm)

EBSD 

settings

Rectangular, 

Cover Area

1 um step 20 % overlap Acq. speed = 2

Speed 2 Resolution 

= (156 pixels x 128 

pixels)

Exposure time ~ 6 

ms

Saved EBSD 

patterns

3.3.3 Laser scanning confocal microscopy

As described above, multiple single laser tracks and 2D pads of laser tracks were produced on bare 

metal plates of IN718 while measuring the dynamic laser coupling in situ. These plates, AMB2022-718-

SH1-BP4 (single laser tracks), AMB2022-718-SH1-BP5 (X-pads), and AMB2022-718-SH1-BP6 (Y-pads), 

were measured ex situ using laser scanning confocal microscopy. The complete 3D surface profiles of 

the laser tracks and pads were measured to extract information on the height profiles under steady 

state conditions, the mass accumulations and losses at the ends of the tracks, the shapes of the chevron 

features, and the effect of multiple adjacent tracks on the height profiles. No challenge problems will be 

associated with these measurements; however, the results and data will be released in July 2022 for 

model comparisons.

4. Description of Benchmark Challenge Problems

4.1 Single Laser Track Benchmarks

4.1.1 CHAL-AMB2022-03-TTAM

Modelers are to calculate the single track ‘time above melting’ as close as possible to the definition 

described in Section 3.1 for all seven combinations of laser power, scan speed, and spot size listed in 

Table 2. Modelers should provide a TAM during steady state for each of the of the seven parameter 
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combinations rounded to three significant digits, in units of seconds. Modelers will be judged by 

calculating the RMS error between the modeled and measured values, as follows:

∆TAM = √∑(TAMi − TAMi,model)

7

i=1

2

A template for submissions is provided here. Note that TTAM, TSCR, and TLCR challenges are included 

in the same template, but are considered separate challenges.

4.1.2 CHAL-AMB2022-03-TSCR

Modelers are to calculate the single track ‘solid cooling rate’ as close as possible to the definition 

described in Section 3.2 for all seven combinations of laser power, scan speed, and spot size listed in 

Table 2. Modelers should provide a SCR for each of the of the seven parameter combinations rounded 

to three significant digits in units of °C/s. Modelers will be judged by calculating the RMS error between 

the modeled and measured values, as follows:

∆SCR= √∑(SCRi − SCRi,model)

7

i=1

2

The measurement, judging, and model comparison notes described in the TTAM section, above, also 

apply to the TSCR competition. A template for submissions is provided here. Note that TTAM, TSCR, and 

TLCR challenges are included in the same template, but are considered separate challenges.

 

4.1.3 CHAL-AMB2022-03-TLCR

Modelers are to calculate the single track ‘liquid cooling rate’ as close as possible to the definition 

described in Section 3.2 for all seven combinations of laser power, scan speed, and spot size listed in 

Table 2. Modelers should provide a LCR for each of the of the seven parameter combinations rounded to 

three significant digits. Modelers will be judged by calculating the RMS error between the modeled and 

measured values, as follows:

∆LCR = √∑(LCRi − LCRi,model)

7

i=1

2

The measurement, judging, and model comparison notes described in the TTAM section, above, also 

apply to the TLCR competition. A template for submissions is provided here. Note that TTAM, TSCR, and 

TLCR challenges are included in the same template, but are considered separate challenges.

4.1.4 CHAL-AMB2022-03-TMPG
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The measurement average and standard deviation for each case number are determined from three 

repeat tracks and four cross-sections (P1, P2, P3, and P4). Predict the average melt pool depth and width 

for the seven case numbers at the midpoint along the track length in micrometers. Modelers will be 

judged by calculating the RMS error between the modeled and measured values, as follows:

∆TMPG = √∑(dti − dti,model)

2

7

i=1

+ √∑(wti − wti,model)

2

7

i=1

A template for submissions is provided here. Please note that this template is updated from the original 

version.

4.2 Laser Pad Benchmarks

4.2.1 CHAL-AMB2022-03-PTAM 

Modelers are to calculate ‘time above melting’ as close as possible to the definition or algorithm 

described in the 3D build CHAL-AMB2022-01-TAM. Modelers should calculate TaM values within the Xpads and Y-pads (described in Figure 4 and Figure 5), excluding the additional line adjacent to the Y-pad. 

Modelers should then calculate the following statistical features for the CHAL-AMB2022-03-PTAM 

modelling challenge:

● Number of pixel/element/nodes that TaM is interrogated from model results (e.g., sample size)

● Mean of all pixel/element/nodal TaM values

● Median of all pixel/element/nodal TaM values

● Standard deviation of all pixel/element/nodal TaM values 

The measurement, judging, and model comparison notes described in the TTAM section, above, also 

apply to the PTAM competition. Additionally, modelers should supply pictures and/or a brief 

description of the model formulation (e.g., finite element, finite difference, boundary element, etc.) and 

visualizations of results. These will be used by AM-Bench organizers to select and request submission of 

invited papers to a special journal issue. 

Note that it is not expected that the AM simulation outputs exactly replicate the temporal, spatial, or 

temperature resolution or range of the thermographic imaging system, and model formulations may 

utilize certain approximations that render results outputs that are less-physically equivalent to the 

thermographic measurements described in Section 3.1. Therefore, participants should consider the 

following: 

1) In calculating the above statistical features, modelers should reject values outside the 

measurable/calculable TaM results (e.g., reject ‘0’ values). Modelers may also wish to reject 

statistical outliers. 

2) Depending on the model formulations, modelers may also consider testing or utilizing different 

algorithms or definitions of ‘time above melt’ (e.g., using a different threshold temperature). 

However, for the modeling challenge, model results will be compared against measurement 

results as described in Section 3.1. Only one entry from each participating research group will 

be used for the challenge judging.
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17

A template for submission is provided here.

4.2.2 CHAL-AMB2022-03-PSCR

Modelers should calculate SCR values as close as possible to the definition or algorithm described in the 

3D build CHAL-AMB2022-01-SCR. Modelers should calculate SCR values within the X-pads and Y-pads 

(described in Figure 4 and Figure 5), excluding the additional line adjacent to the Y-pad. Modelers 

should then calculate the following statistical features for the CHAL-AMB2022-03-PSCR modeling 

challenge:

● Number of pixel/element/nodes that SCR is interrogated from model results (e.g., sample size)

● Mean of all pixel/element/nodal SCR values

● Median of all pixel/element/nodal SCR values

● Standard deviation of all pixel/element/nodal SCR values 

The measurement, judging, and model comparison notes described in the TTAM and PTAM sections 

above also apply to the PSCR competition.

4.2.3 CHAL-AMB2022-03-PMPG

The measurement average and standard deviation are determined for odd and even track numbers on 

cross-sections (e.g., AMB-2022-718-SH1-BP2-P2-Odd, AMB-2022-718-SH1-BP2-P2-Even). For BP2, Odd 

numbered tracks scan in the +X direction and even numbered tracks scan in the -X direction. For BP3, 

Odd numbered tracks scan +Y direction and even numbered tracks scan in the -Y direction. Note the pad 

starting points are indicated in Figure 4 and Figure 5 by the green circles. Predict the average melt pool 

depths and widths as described in Section 3.3 for odd and even track numbers for each cross-section in 

micrometers (two cross-sections for BP2 and four cross-sections for BP3). Cross-section positions are 

given in Figure 11. Modelers will be judged by calculating the RMS error between the modeled and 

measured values, as follows:

∆PMPG = √∑ ((xi − xi,model)

2

Odd + (xi − xi,model)

2

Even)

4

i=1

, 

x1 = dp, x2 = do, x3 = wp, x4 = wo.

A template for submissions is provided here. Please note that this template is updated from the original 

version.

5. Description and Links to Associated Data

All data available to support the AMB2022-03 challenges are linked directly within this document. 

Updates and/or changes to download URLs may be made periodically. Users should refer to the top of 

this document or webpage for updates. 

6. References

Citations are provided throughout this document as hyperlinked URLs to the associated digital object 

identifier (DOI). Clicking these hyperlinked text should open the associated publication or cited source.
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18

†Disclaimer

The National Institute of Standards and Technology (NIST) uses its best efforts to deliver high-quality 

copies of the AM Bench database and to verify that the data contained therein have been selected on 

the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall 

not be liable for any damage that may result from errors or omissions in the AM Bench databases.

Certain commercial equipment, instruments, or materials are identified in this paper in order to specify 

the experimental procedure adequately. Such identification is not intended to imply recommendation 

or endorsement by NIST, nor is it intended to imply that the materials or equipment identified are 

necessarily the best available for the purpose.