Private MachPro Planner Reference

2026-10-01

1 This is entirely AI generated, but based on my understanding of the planners, and with temporary access to the unreleased M31 setup doc - which matches the unreleased MachPro.

The draft M31 manual answers several of the questions that were unresolved in the previous outline. Most importantly, it confirms that PureMotion is not just a marketing label: MachPro exposes it as a selectable trajectory mode, PureMotion uses a configurable Jerk Time, and MachPro provides separate jerk-time settings for Feed, Rapid, and Jog motion. MachMotion Support

It also confirms several application principles that should become part of the reference guide: establish stable axis velocity and acceleration before changing planners; test coordinated motion after single-axis tuning; use air cutting only for initial settings; and use representative cutting to establish final Feed Velocity and Feed Acceleration. MachMotion Support

Below is the updated structure I would recommend.

Motion Planner ReferenceIntroduction

1.1 Purpose and scope

A motion planner calculates the commanded trajectory and controls changes in velocity and acceleration.

MachPro provides two primary motion planners:

• Trapezoidal

• PureMotion

The motion planner affects how MachPro changes velocity and acceleration during machine motion. Planner selection can affect vibration, mechanical response, stable acceleration, and cycle time.

This reference explains:

• The function of each planner.

• The settings that affect planner behavior.

• How planner behavior interacts with axis motion limits.

• How to select a planner for an application.

• How to identify incorrect planner settings.

Confirmed from the M31 draft manual

MachPro selects the active planner with:

Configure > Control > Defaults > Trajectory Mode

The available selections are Trapezoidal and PureMotion. planners.

This reference follows the relevant M31 setup topics: axis configuration, motor motion settings, final machine testing, advanced behavior, parameter reference, troubleshooting, and application notes. Wiring and installation procedures remain in the setup manual.

M31 Motion Control Setup Manual:  Open Document 

==Confirm the supported MachPro mustbuild. beThe disabledsource beforedraft identifies the release planned for 15 October 2026 and later; a minimum build number is not supplied.==

2 Axis Configuration

2.1 Identity and calibration

An Auxiliary axis performs a machine function outside coordinated toolpath motion, such as an automatic tool changer. It does not limit coordinated toolpath velocity or acceleration.

Axis calibration establishes units and initial motion values. Those values are starting points, not verified operating limits for the installed machine.

Axis type and calibration setup:  Open Document 

2.2 Motion Limits

The axis Motion Limits tab is read-only. It shows velocity, acceleration, jerk, and the effective minimum limits across the motors assigned to the axis.

During coordinated motion, MachPro synchronizes the participating axes. Each motor contributes to the effective motion limits; the most restrictive applicable limit can constrain the complete move. Auxiliary axes are excluded.

For Trapezoidal, compare acceleration-rate limits. For PureMotion, compare Constant Acceleration Time and Jerk Time limits. A limiting axis can prevent a coordinated move from benefiting from faster settings on other axes.

Coordinated-motion tests:  Open Document 

3 Motor Configuration

3.1 Units

Before you changestart

the

Calibration setting.sets TestUnits. velocityIncorrect displayed units require a calibration correction. Motors, drives, transmissions, structure, load, lubrication, and accelerationmechanical againcondition afterdetermine youpractical changemotion the planner.limits.

Questions

MachPro stillprovides toseparate answer

limits for:

QuestionMotion type	Why it is requiredFunction
Is planner selection a MachPro-wide setting or can a machine profile override it?Feed	DefineCommanded configurationmachining scope.motion
Does the M31 execute the complete trajectory profile, or does MachPro calculate part of the trajectory before it sends commands to the M31?Rapid	DefineNon-cutting software and controller responsibilities.positioning
Do non-M31 motion controllers implement both planners identically?Jog	DefineOperator-commanded whethermanual this is a MachPro reference or an M31-specific reference.
Which MachPro versions support PureMotion?	Define applicability.
Does planner selection require only Apply/OK, or are there cases where MachPro or the M31 must restart?	Define when the change becomes active.motion

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2. Motion-planning concepts

2.1 Commanded trajectory

The commanded trajectory is the planned path and motion profile that MachPro uses to move the machine.

For coordinated motion, MachPro keeps the commanded axes synchronized. Each participating axis must remain within its configured motion limits.

An axis with a lower acceleration capability can limit the complete coordinated move. For example, if the X-axis can reliably use 500 units/s² and the Y-axis can use only 300 units/s², the Y-axis can limit an X-Y move. Increasing only the X-axis acceleration does not improve that move.

MachPro does not include an axis configured as Auxiliary in coordinated toolpath motion. An Auxiliary axis therefore does not limit the velocity or acceleration of coordinated toolpath moves.

Questions still to answer

Question	Required information
How does MachPro calculate the allowable trajectory velocityVelocity and acceleration from individual axis limits?	Needed for the mathematical reference.
Does the planner use vector projection of trajectory acceleration onto each axis?	Needed for diagonal-move explanation.
How are rotary axes combined with linear axes?	Needed for 4-axis and 5-axis machines.
How are mixed linear/rotary feed rates interpreted?	Needed for coordinated rotary machining.
Are slave motors considered independently, or only through their parent axis limits?	Important for gantry machines.

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3. Feed, Rapid, and Jog motion

MachPro provides separate motion limits for three motion types:

• Feed: commanded machining motion.

• Rapid: non-cutting positioning motion.

• Jog: manual axis motion commanded by the operator.

Velocity is the maximum commanded axis speed. Acceleration controls how quickly the axis changes velocity.

The motor, drive, transmission, machine structure, axis load, and lubrication can limit both values.

Rapid and Jog moves do not have cutting load. Their final velocity and acceleration limits can therefore be different from the values that are reliable during cutting. For Rapid motion, high acceleration can have more effect than high maximum velocity on short moves. For Jog motion, predictable starts and stops are more important than maximum performance.

PureMotion also provides separate Jerk Time settings for Feed, Rapid, and Jog motion.

Questions still to answer

Question	Required information
Are Feed, Rapid, and Jog Jerk Time values stored for each axis?	Define parameter scope.
Does a coordinated Feed move use each axis's individual Jerk Time?	Important for multi-axis synchronization.
Must Jerk Time values be matched between coordinated axes?	This should not be assumed.
Does Jog use the same PureMotion algorithm as programmed motion?	Define behavioral consistency.
Does Feed Hold use Feed, Rapid, or a separate deceleration profile?	Important operational behavior.

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4. Velocity and acceleration

4.1 Velocity

Velocity is the maximum commanded axis speed.

A move requiresneeds enoughsufficient distance to reach theit; configured maximum velocity. Aa high velocity setting does not guarantee that a short move willreaches reachmaximum that value.velocity.

4.2

Acceleration Acceleration

Entry switches between Units/s² and Time (ms). It changes the displayed and entered representation, not the selected planner.

AccelerationThe controlsactual howacceleration quicklysettings velocityare changes.defined in the planner comparison. Velocity and acceleration must operate reliably together.

Single-axis tuning and operating margins:  Open Document 

Coordinated Feed motion

Higher stable acceleration can reducereduces move time even when a short move never reaches maximum velocity. This is especially important for CAMboth toolpathslong that contain manyand short moves.

The M31 setup procedure gives special attention to Feed Acceleration because short toolpathShort moves oftencan doremain notbelow havetarget enoughvelocity distanceand tostill reachfinish maximumsooner with higher acceleration. Feed Velocity. In these cases, increasing stable acceleration can reducetherefore affect cycle time more than increasing maximum velocity.

Feed

4.3 Acceleration display

MachPro can display acceleration as:

• Units/s²

• Time (ms)

Units/s² shows the rate of velocity change.

Time (ms) shows the time associated with the configured acceleration portion of the displayed motion profile.

Changing the display format does not change the selected motion planner.

This distinction is important. Acceleration Time is not Jerk Time.Velocity

Questions still to answer

Question	Required information
What exact relationship does MachPro use to calculate the Time (ms) acceleration display?	Needed for parameter-reference precision.
Is the displayed time based on zero-to-configured-velocity acceleration?	Likely, but must be confirmed.
Does the time display account for PureMotion Jerk Time?	Important because it could otherwise confuse users.
Are acceleration and deceleration always symmetrical?	Do not assume this.

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5. Jerk and Jerk Time

5.1 Jerk

Jerk is the rate of change of acceleration.

PureMotion uses Jerk Time to control how quickly acceleration changes.

Jerk Time is therefore not constant-velocity time and is not the same as the acceleration-time display.

5.2 Effect of Jerk Time

The Trapezoidal planner changes commanded acceleration immediately at an acceleration transition.

PureMotion can spread this change over the configured Jerk Time.

Increasing Jerk Time increases the time required to change acceleration. This smoother transition can reduce vibration, mechanical excitation, and other unwanted machine response.

In some applications, the reduction in mechanical excitation can permit a higher stable velocity or acceleration. The resulting cycle time can therefore decrease even though each individual acceleration transition takes more time.

A Jerk Time of 0 ms removes the PureMotion smoothing effect for that motion type.

5.3 Application

Configure Jerk Time only after velocity and acceleration are stable.

Use the lowest Jerk Time that gives the required result.

The current M31 setup procedure uses this sequence:

1. Start with a low Jerk Time.

2. Increase it in small increments only when necessary.

3. Test machine vibration and mechanical response.

4. Determine whether the change permits a higher stable acceleration.

5. Check the effect on cycle time.

6. Use the lowest value that gives the required result.

Questions still to answer

Question	Required information
What is the permitted Jerk Time range?	Required for a parameter reference.
What are the factory defaults for Feed, Rapid, and Jog?	Required for setup and troubleshooting.
What increment or resolution does the setting support?	Required for precise tuning instructions.
Does PureMotion use constant jerk during the transition?	Fundamental mathematical definition.
Is the acceleration transition linear with time?	Determines whether PureMotion is a conventional S-curve.
Does PureMotion use the same Jerk Time for acceleration and deceleration?	Do not assume symmetry.
Does a 0 ms Jerk Time make PureMotion mathematically identical to Trapezoidal motion?	The manual only states that it removes the smoothing effect.
Are there internal minimum smoothing or controller filters that remain active at 0 ms?	Important before claiming equivalence.

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6. Trapezoidal planner

6.1 Function

The Trapezoidal planner changes commanded acceleration immediately at an acceleration transition..

For a sufficiently long move,PureMotion, a conventional trapezoidal velocity profile contains:

1. Acceleration.

2. Constant velocity.

3. Deceleration.

For a short move, the machine can begin deceleration before it reaches maximum velocity. The velocity profile can therefore become triangular.

The important MachPro-specific characteristic is the abrupt commanded acceleration transition.

6.2 Application

Use the Trapezoidal planner when the machine remainsshorter stable atConstant theAcceleration requiredTime velocity andincreases acceleration and smoother acceleration transitions do not improve the application.

The M31 draft manual states that if both planners provide stable motion at the required acceleration, planner selection is not an important tuning factor.

This statement is useful because it prevents PureMotion from being presented as an automatic upgrade or universally preferred planner.

6.3 Expected behavior

Because acceleration changes immediately at transition points, the Trapezoidal planner can produce a stronger transient mechanical response than PureMotion on machines that are sensitive to rapid changes in acceleration.

This does not mean that the Trapezoidal planner causes vibration on a mechanically sound machine.

Questions still to answer

Question	Required information
Does MachPro's Trapezoidal planner use mathematically constant acceleration between transitions?	Confirm implementation.
Is any acceleration filtering applied by the M31 after the planner output?	Needed to describe actual commanded behavior.
Does the Trapezoidal planner have any internal jerk limiting that is not user-configurable?	Important for comparison with PureMotion.
Does it use the same path look-ahead and cornering algorithm as PureMotion?	Needed to isolate the difference between planners.

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7. PureMotion planner

7.1 Function

PureMotion smooths acceleration transitions by spreading the commanded acceleration change over the configured Jerk Time.

Use PureMotion when abrupt acceleration changes cause vibration or another unwanted machine response.

The purpose is not simply to make motion slower or softer. The useful result occurs when smoother acceleration transitions improve machine response or allow a higher stable acceleration.

7.2 Performance interaction

Additional Jerk Time can increase or decrease total cycle time.

A longer acceleration transition adds time locally. However, if the smoother response allows the machine to operate reliably at a higher acceleration or velocity, total cycle time can decrease. The complete machine must therefore be tuned as a system.

7.3 Motion types

MachPro has separate PureMotion Jerk Time values for:

• Feed

• Rapid

• Jog

A value of 0 ms removes PureMotion smoothing for the applicable motionvelocity type.

change.

Questions still to answer

Rapid

andJog

Question	Required information
What mathematical motion profile does PureMotion use?	Still the largest missing technical definition.
Is PureMotion accurately described as an S-curve planner?	Do not lower Feed Velocity solely because short moves do not reach it. Participating-motor constraints are described in Motion Limits. For tests, use thisthe termsetup untillink engineeringthere. confirms it.
Doesmotion Rapid and Jog have no cutting load, so their reliable limits can differ from Feed limits. Higher Rapid velocity is most useful with sufficient travel; short positioning moves can be acceleration-limited. Jog settings must retain predictable starts, stops, and manual control. Configuration procedures:  Open Document  Motor Units motion graph The graph shows the commanded profile. It extends the displayed timeline to reach configured maximum velocity, even when an actual move is too short to reach that velocity. It does not predict the time of a specified machine move. Trapezoidal shows the acceleration-rate profile. PureMotion alterincludes onlyboth jerk transitions and its constant-acceleration transitions,portion; see PureMotion Jerk Time. The setup comparison graphics use red for Rapid, green for Feed, velocity vertically, and time horizontally. Matching scales permit direct comparison. Actual speed, move time, and reliability require machine tests; see Final machine test. Select the motion planner Trajectory Mode is located at Configure > Control > Defaults. It selects Trapezoidal or also corner blending and velocity planning?	Critical distinction.
Does PureMotion use a different look-ahead algorithm?	Needed for short-segment and contour behavior.
Does PureMotion change geometric path tolerance?	Critical for accuracy documentation.
Does PureMotion behave differently on arcs than on line segments?	Needed for contouring reference.
Does it apply to synchronized spindle motion such as threading or tapping?	Special-motion applicability.
Does it apply to probing?	Probing stop behavior can require different handling.

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8. Planner comparison

.

Characteristic	Trapezoidal	PureMotion
AvailablePlanner in MachProorder	Yes2nd Order	Yes3rd Order S-curve
SelectedActual inacceleration Trajectory Modesetting	YesAcceleration rate, units/s²	YesConstant Acceleration Time, ms
CommandedAlternate acceleration transitiondisplay	ImmediateCorresponding Time (ms)	SpreadCorresponding overUnits/s²
Acceleration transitions	Direct changes between zero and the configured rate	Gradual transitions controlled by Jerk Time
User-configurable Jerk Time	Not identifiedused	YesSeparate Feed, Rapid, and Jog settings
Feed Jerk TimeAcceleration/deceleration	NotSame applicable as PureMotion smoothingsetting	YesSame settings, reversed profile
RapidTypical Jerk Timeapplication	NotRequired applicableperformance aswithout PureMotionS-curve smoothing	YesSmoother transitions improve machine response or stable performance
Jog

For a long Trapezoidal move, the velocity profile has acceleration, constant velocity, and deceleration. A shorter move can have a triangular profile because deceleration starts before maximum velocity is reached.

PureMotion can reduce excitation caused by abrupt acceleration transitions. If both planners meet the application requirements, planner selection is not a primary tuning factor. Neither planner is universally better.

Planner selection and retesting:  Open Document 

PureMotion Jerk Time

Not

Jerk is the rate of change of acceleration. Jerk Time controls the transitions into and out of constant acceleration and deceleration. Constant Acceleration Time specifies the constant-acceleration portion.

The complete acceleration profile is:

Jerk transition → Constant Acceleration Time → Jerk transition

Total acceleration time = Constant Acceleration Time + (2 × Jerk Time)

For example, 250 ms of Constant Acceleration Time and 25 ms of Jerk Time give 300 ms total. Deceleration uses the reversed profile, with no separate acceleration/deceleration settings.

A shorter Constant Acceleration Time produces a higher acceleration rate for the applicable asvelocity PureMotionchange. smoothingA Yeslonger value produces a lower rate. Increasing Jerk Time makes transitions more gradual; 0 ms behavior Not applicable Removes PureMotionremoves smoothing for that motion typetype.

PureMotion does Primarynot applicationdirectly Stabletune motiona withoutvibration additionalfrequency. Jerk Time changes acceleration smoothingtransitions Reducethat unwantedcan responseexcite fromvibration. abruptConstant Acceleration Time affects acceleration changesrate, which can Canalso affectexcite cyclemechanical timeresonance.

Yes

Longer Yestransitions can increase Canmove permittime. If smoothing permits higher stable accelerationvelocity Machine dependent Potentially, when smoothing reduces unwanted response Requires velocity/acceleration tuning first Yes Yes

Do not present either planner as universally better.

If both planners give stable motion at the requiredor acceleration, planneroverall selectioncycle is not an important tuning factor.

Questions still to answer

Add rows for:

• Look-ahead.

• Cornering algorithm.

• Path tolerance.

• Arc processing.

• Exact-stop behavior.

• Feed Hold behavior.

• Probing.

• Threading.

• Tapping.

• Synchronized motion.

These rows should remain incomplete until engineering confirms the implementation.

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9. Coordinated motion

Configure and test each axis individually before you test coordinated motion.

During coordinated motion, MachPro keeps the commanded axes synchronized. An axis with a lower acceleration capabilitytime can limitdecrease. Evaluate the complete move.machine cycle.

AfterThe single-axisM31 tuning,setup test:manual gives 10 ms as an initial tuning value and describes 50 ms as high. These are tuning guidance, not a factory default or a permitted maximum.

Jerk-time

• tuning:  Open Document 

  Copy settings to other motors

  LongCopied moves.

  values
are
• starting

  Shortpoints moves.

  unless
equivalent
• operating

  Alllimits directionshave ofbeen travel.

  verified.
The
• copy-control

  Differentprocedure positionsis in usableMotor Units setup:  Open Document 

  3.2 Final machine test

  Accept settings when representative production motion meets position accuracy, drive stability, machining quality, and cycle-time requirements without position loss, faults, excessive vibration, or mechanical instability.

  Air cutting establishes initial settings; representative cutting establishes final Feed limits. Machine response can change with travel position, direction, axis travel.combination, tooling, workholding, and load. Significant changes require renewed verification.

Final

• testing and limiting-axis diagnosis:  Open Document 

  4 Advanced Options and Information

  4.1 Path blending and exact stop

  Acceleration-profile selection, path blending, exact-stop behavior, and path tolerance are different functions. The available M31 material does not define their complete interaction. See Unresolved questions before adding planner-specific claims.

  4.2 Look-ahead and special motion

  Short-move acceleration behavior is described in Coordinated Feed motion.

  motion.
It
• does

  Directionnot changes.

  establish
MachPro's
• look-ahead

  Representativedepth Rapidor motion.

  queue
behavior,
• or

  Representativethe Jogselected motion.

  planner's
behavior
• during

  Normalprobing, productionthreading, materialstapping, and cuttingsynchronized conditions.spindle motion. These remain unresolved.

5

Reference

IfInformation coordinated

5.1 motionParameter is less stable than single-axis motion, identify the limiting axis or axis combination. The M31 draft currently instructs the user to decrease the applicable velocity, acceleration, or Jerk Timelocations and test again.

Documentation issue to verify

The instruction to decrease Jerk Time when coordinated motion is unstable deserves engineering review.

Elsewhere, the same manual states that increasing Jerk Time smooths acceleration transitions and can reduce unwanted mechanical response.

Both statements can potentially be correct in different conditions, but the diagnostic logic is not obvious. The reference manual should state when an unstable condition calls for:

• Lower acceleration.

• More Jerk Time.

• Less Jerk Time.

Without that distinction, the troubleshooting instruction can appear contradictory.

Questions still to answer

definitions accelerationfeature.conditions resolveambiguity.

QuestionSetting	RequiredLocation informationor owner	Definition
DoesTrajectory coordinated PureMotion require equal Jerk Time on all participating axes?Mode	ImportantConfigure and> currentlyControl unanswered.> Defaults	Planner selection
If axes have different Jerk Time values, how does the planner synchronize them?Units	CoreAxis coordinated-motioncalibration; behavior.displayed in Motor Units	Axis calibration
CanFeed, oneRapid, axis'sJog Jerk Time limit the entire trajectory?Velocity	SimilarMotor toUnits	Velocity limiting.and motion types
HowAcceleration does MachPro report which axis limits a move?Entry	ImportantMotor diagnosticUnits	Display/entry representation
UnderTrapezoidal whatacceleration	Motor shouldUnits, by motion type	Planner comparison
PureMotion Constant Acceleration Time	Motor Units, by motion type	PureMotion profile
Feed, Rapid, Jog Jerk Time be decreased instead of increased?	RequiredMotor toUnits	PureMotion currentJerk draftTime
Effective axis limits	Axis Motion Limits, read-only	Motion Limits

---

==Collect

10.factory Motordefaults, Unitspermitted motionranges, graph

increments,

storage scope, controller restrictions, and when each parameter change takes effect. The Motortuning Unitsvalues graphabove showsdo thenot commandedsupply motionthese profile.specifications.==

Do not use this graph to predict actual move time.

The

5.2 graphUnresolved extends its displayed timeline as necessary to let the profile reach configured maximum velocity. A high velocity setting can therefore show a complete acceleration, constant-velocity, and deceleration profile even when a real machine move does not have enough distance to reach that velocity.

Use machine testing to determine:

• Whether a move reaches maximum velocity.

• Actual cycle time.

• Repeatable stability.

• Behavior under representative cutting load.

The current graph uses:

• Red lines for Rapid motion.

• Green lines for Feed motion.

• Vertical scale for axis velocity.

• Horizontal scale for move time.

The graphs are scaled for direct comparison.

Questions still to answer

questions

QuestionTopic	RequiredInformation informationto confirm
DoesSoftware/controller responsibility	==Which trajectory calculations run in MachPro and which run in the graphM31? showConfirm theequivalent selectedbehavior planneron accuratelysupported fornon-M31 both Trapezoidal and PureMotion?	Important interpretation question.controllers.==
DoesPlanner itscope graphand Jerk Time explicitly or only its effect on velocity?switching	Needed==Confirm forprofile/global userscope, interpretation.the G-codes that switch planners, their scope and persistence, and whether any configuration changes require a restart. The draft says G-code can change planners, but supplies no commands.==
CanCoordinated the graph display acceleration?geometry	Useful==Confirm formixed PureMotionlinear/rotary explanation.feed interpretation and effective-limit calculation. Add projection mathematics only if needed to explain configuration or diagnosis.==
CanPureMotion profile	==Confirm constant jerk during transitions and how short moves truncate or scale the graphconfigured showtime Jog motion?	Current note identifies Rapid and Feed only.periods.==
DoesJog and stopping	==Confirm Jog profile behavior and the graphdeceleration/queue calculatebehavior coordinated-axis motion or only individual-axis profiles?	Important scope limitation.

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11. Planner-selection workflow

Do not use planner selection to compensateused for incorrect axis settings.

Use this sequence:

1. Complete axis calibration.

2. Establish stable axis velocity.

3. Establish stable axis acceleration.

4. Test velocity and acceleration together.

5. Test the full usable axis travel.

6. Establish initial Feed settings with unloaded motion.

7. Verify final Feed Velocity and Feed Acceleration under representative cutting load.

8. Select the applicable planner.

9. If you use PureMotion, adjust Jerk Time only after velocity and acceleration are stable.

10. Test coordinated motion.

11. Verify part quality, vibration, machine stability, and cycle time.

The M31 draft recommends initially setting operating velocity and acceleration to 80% of the highest repeatable stable values found during testing.

That 80% value belongs primarily in the setup/how-to manual. In this reference guide, it should appear only as a cross-reference or application note, not as part of the planner definition.

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12. Verification criteria

Planner tuning is complete when representative production motion is reliable and gives the required machining quality and cycle time.

Verify that the machine has no:

• Position errors.

• Drive faults.

• Loss of position.

• Excessive vibration.

• Mechanical instability.

For Feed motion, use test cuts to determine the final Feed Velocity and Feed Acceleration.

Do not use air cutting alone to determine final Feed settings. A machine can operate correctly without cutting load and fail when normal cutting forces are present.

Questions still to answer

Question	Required information
What MachPro diagnostics should be monitored during planner testing?	Make testing repeatable.Hold.==
CanPath MachPro display following error during a test?control	Important for servo systems.
Can planner-limited velocity be distinguished from drive-limited velocity?	Important troubleshooting distinction.
Is there a standard MachMotion validation program for planner testing?	Would improve consistency.
What constitutes excessive vibration?	Qualitative guidance may be enough if no numeric specification exists.

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13. Path blending and exact-stop behavior

This section is still required, but the M31 draft manual does not provide enough information to complete it.

A planner reference must distinguish:

• Acceleration-profile selection.

• Path blending.

• Exact-stop behavior.

• Path-tolerance behavior.

These are related functions but are not the same setting.

Questions that must be answered

G-codes;PureMotionthatselectionindividualexact-stop

Question	Required information
Which MachPro G-codes select==Identify exact-stop and continuous-path modes?	Referenceconfirm blending geometry, tolerance, corner velocity, contour error, and whether exact stops use the MachProselected G-code manual.profile.==
DoesLook-ahead	==Confirm operatesupport inwith both exact-stopplanners, algorithm differences, depth, configurability, and blendedcommands modes?	Importantsynchronize planneror behavior.empty the queue.==
DoesSpecial planner selection change blend geometry?motion	Must==Confirm separatebehavior smoothingon fromarcs, contouring.probing, threading, tapping, and synchronized motion.==
How does path tolerance affect corner velocity?Filtering	Important==Confirm forwhether accuracy.filtering modifies the final Trapezoidal output.==
CanGraph plannerscope	==Confirm changeJog contourdisplay errorand atwhether the samegraph path-tolerancerepresents setting?	Needsor verification.coordinated axes.==
DoesDiagnostics	==Identify modelimiting-axis usediagnostics, following-error display, and how to distinguish planner limits from drive limits.==
Validation	==Confirm a standard test program, acceptance criteria for vibration, and guidance for rounded corners, segment pauses, and unequal axis response.==
Setup consistency	==The M31 overview states 80% operating values and 20% margin; its detailed procedures state 80–90% and 10–20%. Confirm the selectedintended guidance and how the acceleration profilemargin whenis stopping?converted to PureMotion time.==
Published links	Important==Confirm distinction.that the published M31 page contains the working manual's HTML anchor IDs. The private page was unavailable for verification.==

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6

14.Troubleshooting

Look-ahead

6.1 Vibration or oscillation

Vibration can indicate excessive motion demand, abrupt transitions, mechanical defects, resonance, drive instability, or cutting-condition problems. Definitions and short-segmentphysical motioneffects

Theare M31in draftMechanical confirms that short moves can be acceleration-limited and that higher stable Feed Acceleration can reduce cycle time even when maximum Feed Velocity is never reached.response.

ThisPureMotion givesaddresses aacceleration-transition strongexcitation; reason to include a look-ahead section, but the draftit does not definecorrect MachPro'severy look-aheadcause implementation.

of

Questionschatter. thatCutting-only mustvibration becan answered

originate intooling,workholding,spindle

Question	Required information
Does MachPro use look-ahead with both planners?	Fundamental behavior.
Is look-ahead identical between Trapezoidal and PureMotion?	Needed for comparison.
How deep is look-ahead?	Blocks, time,condition, or pathcutting distance.
Is it configurable?	Parameter reference.
Which commands cause the planner queue to synchronize or empty?	Important for M-codes, probing, macros, and outputs.
How does Feed Hold affect queued motion?	Operational behavior.

---

15. Parameter reference

Each motion-planner parameter should have a standardized reference entry.parameters.

Use these fields:

Field	Required content
Setting name	Exact MachPro label
Menu location	Exact configuration path
Function	What the setting controls
Applies to	Trapezoidal, PureMotion, or both
Motion type	Feed, Rapid, Jog, or all
Scope	Axis, motor, or global
Units	Exact units
Default	Factory value
Minimum	Lowest permitted value
Maximum	Highest permitted value
Resolution	Smallest supported increment
Higher value	Expected result
Lower value	Expected result
Interaction	Related settings
Takes effect	When the new value becomes active
Incorrect setting symptoms	Observable machine behavior
Diagnostic action	What to check next

At minimum, this reference should include:

• Trajectory Mode

• Feed Velocity

• Feed Acceleration

• Feed Jerk Time

• Rapid Velocity

• Rapid Acceleration

• Rapid Jerk Time

• Jog Velocity

• Jog Acceleration

• Jog Jerk Time

• Acceleration display mode

Missing values to collect

For each setting, collect:

• Default.

• Minimum.

• Maximum.

• Increment.

• Storage scope.

• Axis or motor ownership.

• Any controller-specific restrictions.

---

16. Troubleshooting

Vibration at acceleration transitions

Possible causes include:

• Acceleration is too high.

• Abrupt Trapezoidal acceleration transitions excite the machine structure.

• Mechanical looseness or wear.

• Poor lubrication.

• Drive or servo instability.

• Tooling or workholding problems during cutting.

Diagnostic sequence:steps:  Open Document 

6.2

Determine whether the vibration occurs without cutting.

Verify the mechanical condition of the machine.

Verify stable velocity and acceleration.

If Trapezoidal motion is stable but mechanically harsh, test PureMotion.

Increase PureMotion Jerk Time in small increments if additional smoothing is required.

Test whether the new setting permits a higher stable acceleration.

Verify the result under representative cutting load.

Programmed feed is not reached

DoPossible notconstraints assumeinclude thatmove Feedlength, Velocityacceleration, isparticipating-motor toolimits, low.

direction

Check:

changes,

and
• path

  Movecontrol. length.

  A
short

• Feed Acceleration.

• Participating-axis limits.

• Direction changes.

• Path-planning constraints.

Short movesmove can end before theprogrammed feed is reached. See Short moves and Motion Limits.

Diagnosis and machine hastests: sufficient distanceOpen toDocument reach programmed Feed Velocity.

6.3 Cycle time increases with PureMotion

AdditionalSee PureMotion Jerk Time increasesfor the durationtransition-time/performance oftradeoff. accelerationThe transitions.

Determine whether the smoother motion permits a higher stable acceleration or velocity. Evaluate the complete machine cycle rather than an individual transition.

Questions still to answer

Add confirmed diagnostic guidance for:

• Rounded corners.

• Pauses between short segments.

• Feed Hold behavior.

• Following error during PureMotion acceleration.

• Unequal behavior between axes.

• Different behavior with 0 ms Jerk Timetuning and Trapezoidaltesting mode.procedures are linked there.

• Coordinated-motion instability that improves when Jerk Time is decreased.

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17.7 Application notesNotes

Mechanical7.1 Vibration, oscillation, and mechanical condition

DoOscillation is repeated motion about an equilibrium position. Vibration is unwanted oscillatory motion, such as shaking, buzzing, chatter, or ripple.

Mechanical looseness, wear, excessive backlash, poor lubrication, damaged components, and unstable drives can produce vibration that planner tuning cannot correct. Correct known defects before optimizing motion.

Vibration does not usechange plannerphysical settingsinertia toor hidemoving amass. knownFor mechanicallinear defect.motion, force = mass × acceleration. Acceleration and oscillatory motion create reaction forces that can increase structural deflection, drive load, position error, or following error.

CorrectMechanical problemsresponse suchalso as:

depends

on
• stiffness,

  Excessiveload, backlash.

  position,
direction,
• spindle

  Looseoperation, mechanicaltooling, components.

  workholding,
and
• cutting

  Wornforces. bearings.

  Reduced
vibration
• is

  Incorrectone lubrication.

  verification
result;
• apply

  Damagedthe drivefull components.

  acceptance

• Poor tooling or workholding.

Then optimize planner settings.criteria.

Cutting7.2 load

Cutting load changesand machineplanner response.

choice

Use unloadedthe motiondistinctions toin establish initial settings. Then use representative test cuts to determine final Feed Velocity and Feed Acceleration.

Rapid and Jog motion, dothe notcriteria havein cuttingFinal load.machine Thesetest, and the comparison in Select the motion typesplanner. can therefore use different velocity, acceleration, and Jerk Time settings from Feed motion.

Vibration and resonance

PureMotion can reduce unwanted machine response by smoothing acceleration transitions.

Do not describe Jerk Time as a vibration-frequency setting. It controlsSelect the timeplanner over which acceleration changes.

A machine can have several mechanical resonances. Machine stiffness, moving mass, mechanical wear, axis load, tooling, workholding, spindle operation, and cutting forces can all affect vibration.

Planner selection

Do not select PureMotion only because it is the newer planner.

Use it when its smoother acceleration transition givesfor a measurable application benefit.

If Trapezoidal and PureMotion both give stable motion at the required acceleration, planner selection is not an important tuning factor.

What changed from the earlier outline

The M31 draft lets us convert several previous questions into documented statements. We can now state that PureMotion uses Jerk Time to spread acceleration transitions, that Jerk Time is measured in milliseconds, that Feed, Rapid, and Jog have separate Jerk Time settings, and that 0 ms removes the PureMotion smoothing effect for that motion type. We can also document the exact planner-selection path and the requirement to retest velocity and acceleration after changing planners. MachMotion Support

It also resolves the earlier concern about “acceleration time.” MachPro has an acceleration display that can show either units/s² or Time (ms), but changing that display does not change the planner. That is a separate concept from PureMotion Jerk Time and should be called out clearly in the reference. MachMotion Support

The most important engineering question that remains is still the mathematical definition of PureMotion. The current draft supports saying that PureMotion spreads an acceleration change over Jerk Time, but it does not establish whether the profile uses constant jerk, a conventional seven-segment S-curve, a polynomial transition, or another function. I would avoid calling it an “S-curve planner” until that is confirmed.

I would also flag one internal documentation issue for review before release: the final coordinated-motion section says to decrease velocity, acceleration, or Jerk Time when motion is unstable, while the preceding section says that increasing Jerk Time can reduce unwanted mechanical response. MachMotion Support That may reflect two different failure modes, but the manual needs to state the distinction explicitly.

For Diátaxis, I would now separate the material more firmly. The existing M31 page is primarily a How-to setup document. This proposed planner guide should be Reference, with the short Application notes retained where the user needs conceptual context to interpret a parameter. Procedures such as “find maximum stable acceleration,” the 80% operating-margin method, and progressive Jerk Time testing should remain in or link back to the M31 setup/how-to manual rather than being duplicated extensively in the planner reference.