How to Match and Select Stroke for Each Axis of Multi Axis Linear Module？
Multi-axis combination linear module stroke X/Y/Z axis differentiated stroke matching + condition-based safety margin selection + uniform-stroke error avoidance
Mr. TechMan from Engineering department of TallMan Robotics
A gantry system that jitters at the end of every X-stroke. A Z-axis that can't quite reach the bottom of a deep-draw part. A three-axis platform that resonates every time all axes move together at speed. On the shop floor, these show up as "programming problems" or "module quality issues" — but in most debugging cases we've seen, the root cause was decided months earlier, at the selection stage: X, Y, and Z were specified with the same stroke length and the same flat safety margin, because it simplified procurement and drawing work. Understanding how Multi Axis Linear Module Stroke choices affect your system is critical to avoiding such issues in the first place.
That shortcut is common, and it's not free. Undersized stroke on one axis leaves a dead zone in the process. Oversized stroke on another adds idle mass that shows up as resonance later. This guide walks through how to size each axis independently — using TallMan Robotics' single axis linear module range and published datasheet figures as the concrete reference — how TallMan's own speed and mounting data should shape your margin decision instead of a flat rule of thumb, and how to check the result before it goes into a BOM.
1. The Core Rule: Size Each Axis to Its Own Job, Not to a Shared Number
Multi-axis modules get treated as one component with three motors, but each axis is doing a structurally different job. X handles planar travel. Y usually carries the load. Z handles precision depth. Sizing them identically ignores that, and it's the single most common mistake in early-stage selection.
The selection sequence that avoids it is straightforward:
- Map the actual process motion for each axis — every load, process, inspection, and unload step it has to reach. - Confirm the axis's effective stroke covers that full motion path, with no dead zones at either end. - Check the module's own speed and payload rating at that stroke — not a flat industry margin (see Section 3).
Skipping step 3, or applying one flat number across all three axes, is where most of the downstream problems in Section 4 originate.
2. Sizing X, Y, and Z Independently
2.1 X-Axis — Horizontal Travel
The X-axis is almost always the workhorse of the cycle: feeding, station-to-station transfer, or full-width planar coverage. Its job is repeated motion, often at the highest frequency of the three axes, so the sizing question isn't just "does it reach" — it's "how much unnecessary mass is it dragging back and forth on every cycle."
Set the effective stroke to the maximum horizontal distance the process actually requires, end to end across load, process, inspection, and unload — then stop.
Belt drive is usually the better fit for this axis, and TallMan's datasheet shows why in concrete terms: the TM-B45-CM is rated for a flat 3300 mm/s maximum speed regardless of stroke, versus the screw-driven line, where the maximum safe speed steps down as ordered stroke gets longer (Section 3.1). Standard belt travel tops out at 800 mm before it becomes a custom order — beyond that, check with the factory rather than assuming the standard line covers it. The trade-off is repeatability: belt drive is rated at ±0.04 mm versus ±0.01 mm (or ±0.005 mm on the finer C5 grade) for screw drive — fine for feeding and station transfer, not fine enough if X itself is doing anything precision-critical.
2.2 Y-Axis — The Load-Bearing Span
Y is different in kind, not just degree: it's usually carrying the full weight of the Z-axis, the end effector, and whatever the tool is holding, while spanning the longest distance in the system. That combination — long span plus real mass — means Y sizing is a payload question as much as a coverage question, and TallMan's screw-driven line makes that trade-off explicit rather than hiding it behind one number.
Worked example: a gantry needs to span four fixed stations 280 mm apart while carrying a 90 kg end-of-arm payload. Raw travel requirement: 3 × 280 mm = 840 mm.
On the TM-S135-CM / TM-S135-CR datasheet, payload capacity isn't one number — it's set by which screw lead you order, and the lead also sets the top speed:
Screw lead Rated speed Horizontal payload 5 mm 250 mm/s 95 kg 10 mm 500 mm/s 75 kg 16 mm 800 mm/s* 44 kg 20 mm 1000 mm/s 35 kg
*TallMan's datasheet flags this lead/speed combination with a stroke caveat: above roughly 750 mm ordered stroke, the published 800 mm/s rating requires checking the stroke-vs-speed derating table rather than assuming the nominal figure still applies — TallMan's own note on this table states that exceeding the safe speed for a given stroke risks resonance in the sliding table.
At 90 kg, only the 5 mm and 10 mm leads actually qualify — the faster 16 mm and 20 mm leads are rated well under the load. That means the real selection question isn't "does a 135-body module cover 840 mm of travel" (it does, comfortably, at up to 1250 mm standard stroke) — it's "how fast does this station-to-station move need to happen at 90 kg," because that's what decides which lead, and therefore which cycle time, is actually available. If the process needs faster than ~500 mm/s at this payload, the answer isn't a faster lead on the same body — it's stepping up to a larger body (TM-S150 or TM-S170) that rates more payload at the higher-speed leads.
2.3 Z-Axis — Depth and Precision
Z carries the tightest tolerance of the three, because it's usually doing the part of the process that actually determines quality: dispensing depth, cutting feed, press-fit depth, or vision calibration height. A shortfall here isn't a coverage gap in the abstract sense — it's a part that's out of spec.
Size Z to the full height variation across the process, plus a bit of room for later commissioning adjustment — dispensing height and cut depth tend to get fine-tuned during trial runs more than X or Y travel does.
The detail that generic "just pick a stroke" advice usually misses: Z is almost always mounted vertically, and vertical mounting is where the payload numbers change the most. Two things worth checking against the actual datasheet before assuming a horizontal-rated module will work:
Belt-driven modules aren't rated for vertical use at all. TallMan's TM-B series remark states the synchronous-belt line isn't recommended for vertical mounting — if your Z-axis needs belt-level speed, that's a real constraint to raise with the supplier, not a detail to skip. - Screw-driven vertical payload drops sharply from the horizontal number. On the same TM-S135 datasheet used above, the 5 mm lead rates 95 kg horizontal but only 27 kg vertical; the 10 mm lead drops from 75 kg to 18 kg. A Z-axis carrying, say, 25 kg vertically would clear the 5 mm lead's vertical rating but not the 10 mm lead's — which is the opposite ranking you'd get by looking at horizontal figures alone.
For depth-critical work, repeatability usually decides the model before stroke length does — TallMan's screw-driven line is rated ±0.01 mm standard (C7 grade) or ±0.005 mm on the finer C5 grade, against ±0.04 mm for belt drive. A compact model like the TM-S45-CM (800 mm stroke) or the guide-rail-built-in TM-TH5 (also 800 mm) covers most vertical depth-control needs without carrying stroke the process will never use — but check the vertical payload column for the specific lead, not just the horizontal one.
3. What Actually Sets the Margin: TallMan's Own Speed and Mounting Data in Multi Axis Linear Module Stroke Selection
Generic advice on this topic tends to land on a flat "add 10–20 mm" rule. TallMan's datasheets show two more specific, more useful things happening at the ends of a module's stroke — and neither of them is a number you're supposed to add yourself.
3.1 There's already a mechanical safety distance built into the housing
TallMan's own dimension drawings label a factory-built "safety distance" at each end of a module's effective stroke — this is mechanical clearance already engineered into the housing between the carriage's travel limit and the physical end stop, not something you specify. On the TM-TH guide-rail-built-in series this is documented at 10 mm per end; on the general screw-driven and belt-driven lines it's typically 5 mm per end. It's already priced into the module's overall length (shown on the datasheet as L = S + a fixed offset) — you don't add it on top of your ordered stroke, you just know it's there.
3.2 Speed has to be matched to stroke, not just to load
This is the part that actually functions like a "margin" decision in practice. TallMan's screw-driven datasheets publish a stroke-vs-speed table with a standing note: the rated speed shown for a given stroke is the maximum safe speed at that stroke — run faster than that and the datasheet warns of resonance in the sliding table. Longer ordered strokes bring that safe-speed ceiling down. On the TM-S135/150 family specifically, the datasheet flags stroke lengths above roughly 750–850 mm (the exact threshold depends on model and lead) as the point where the nominal speed rating for a given lead needs to be checked against the derating table rather than assumed.
Practically, this means the "high speed + long stroke needs extra care" rule isn't a rule of thumb you apply — it's a lookup you do against the specific model and lead you're speccing, before you finalize the order.
3.3 Horizontal vs. vertical is a different payload rating, not a margin adjustment
The other place generic advice oversimplifies: "add margin for non-horizontal mounting" implies a small correction. TallMan's data shows it's usually a different number outright — the vertical payload column on the screw-driven line runs 60–75% lower than the horizontal column at the same lead (see the TM-S135 table in Section 2.3), and the belt-driven line isn't rated for vertical use at all. If an axis is mounted vertically or at an incline, size it off the vertical column from the start, not the horizontal one with an adjustment tacked on.
4. What Uniform Stroke Sizing Actually Costs You
Specifying the same stroke across X, Y, and Z is usually a procurement or drafting shortcut, not a deliberate engineering decision — but it produces four distinct failure modes:
Dead zones. If the shared stroke is set to whichever axis needs the least, the other axes can't reach their full process range — incomplete processing, blocked station switching, missed cycle-rate targets. Resonance and wear. Push a screw-driven axis past its stroke-specific safe-speed rating (Section 3.2) and the datasheet's own warning applies: resonance in the sliding table, showing up as jitter and accelerated wear well before it looks like a visible problem. Cost creep. Oversized modules cost more up front, take more floor space, and put more continuous load on the drive motors — a slow bleed on both capex and running cost. Debugging drag. Mismatched axes rarely move in a clean rhythm together; three-axis linkage testing turns up collision and interference that a correctly-sized system wouldn't have produced, and that stretches commissioning time.
The fix isn't complicated, just disciplined: size each axis to its own process (Section 2), check its actual speed and payload rating at that stroke and mounting orientation (Section 3) rather than assuming a flat number, and verify linkage stability after — not instead of — getting the individual specs right.
5. Three-Step Verification Before It Goes to the BOM in Multi Axis Linear Module Stroke Selection
Process coverage. Does each axis's effective stroke cover its full motion path — load through unload — with no dead zone at either end? Datasheet fit. For the ordered stroke and lead, does the payload rating (horizontal or vertical, matching how the axis is actually mounted) cover your load, and does the speed rating at that stroke cover your required cycle time without tripping the resonance warning? Linkage test. Run a full-stroke reciprocating cycle and check specifically for jitter, resonance, and near-limit contact during coordinated three-axis motion.
If you're assembling the BOM against TallMan's multi axis linear module range, cross-check each axis's chosen model and lead against its rated payload at the correct mounting orientation — as the Y- and Z-axis examples above show, that's what disqualifies an undersized model more often than the stroke figure does.
6. Quick Reference: Matching Axis Role of Multi Axis Linear Module Stroke to a Model Series
Axis role Typical drive type What to check first TallMan series X — high-cycle horizontal travel Belt Flat speed rating (e.g. TM-B45-CM: 3300 mm/s to 800 mm stroke) Belt-driven, general environment Y — load-bearing span Screw Payload by lead, not just stroke (see Section 2.2 table) Screw-driven, general environment Y — span beyond ~1250 mm Screw Long-stroke line's payload-by-lead table Long-stroke screw-driven Z — vertical precision depth/lift Screw Vertical payload column specifically, ±0.01/±0.005 mm repeatability Screw-driven or guide-rail built-in
This is a starting filter, not a substitute for reading the exact model's datasheet — as Sections 2.2 and 2.3 show, the number that disqualifies a candidate model is usually payload at the correct mounting orientation and lead, not the stroke figure in isolation.
7. Conclusion
Independent axis sizing, a real check against the module's own speed and payload datasheet instead of a flat margin, and a linkage check before finalizing — that's the sequence that avoids the dead-zone-or-resonance trade-off uniform stroke sizing tends to produce. The numbers that actually decide a model, in our experience working through TallMan's own catalogue, are rarely the stroke figure by itself — they're the lead-dependent payload rating and the mounting orientation. Check those against the datasheet before the stroke number, and stroke mismatch stops being a recurring debugging item.
FAQ about Multi Axis Linear Module Stroke Selection
Q1: What's a reasonable safety margin for a multi-axis linear module's stroke?
Rather than a flat number, check two things on the actual datasheet: the mechanical safety distance is already built into the housing (5 mm per end on most TallMan screw/belt series, 10 mm on the TM-TH guide-rail-built-in line), and the maximum safe operating speed for your ordered stroke — which steps down as stroke gets longer, per the manufacturer's own stroke-vs-speed table.
Q2: Why not just use the same stroke length for X, Y, and Z?
Because they're not doing the same job. X handles repeated planar travel, Y usually carries the load across the longest span, and Z controls process depth (usually vertically mounted, which changes the payload rating outright). Matching one stroke number across all three ignores that each axis's actual model selection is driven by payload-at-lead and mounting orientation, not by the stroke figure alone.
Q3: How should a fast, heavy-load gantry axis be sized?
Check the payload-by-lead table for the specific model — faster leads rate less payload on the same body (see the TM-S135 example in Section 2.2). If the required speed and load combination isn't covered by any lead on your current body size, the fix is a larger body, not a workaround on the current one.
Q4: What failures typically trace back to stroke mismatch?
Limit collisions, carriage jitter or resonance (TallMan's own datasheet explicitly warns of this when the safe-speed-for-stroke rating is exceeded), incomplete process coverage, three-axis linkage interference during commissioning, and accelerated rail/carriage wear.
Q5: Does a Z-axis need different sizing than X or Y because it's usually vertical?
Yes. Vertical payload ratings on TallMan's screw-driven line run well below the horizontal figures at the same lead — roughly 60–75% lower in the TM-S135 example — and belt-driven modules aren't rated for vertical mounting at all. Size Z off the vertical payload column from the start.
Q6: What's a quick way to sanity-check a stroke selection before finalizing?
The three checks in Section 5: full process coverage per axis, payload and speed rating checked against the datasheet at the correct mounting orientation, and a full-stroke linkage test looking specifically for jitter or near-limit contact. Also worth a look: TallMan's effective travel vs. installation travel explainer, which covers a related distinction — the stroke a module is rated for versus what's actually usable once end stops and carriage length are accounted for.
You are welcome to visit our other social media or video gallery as follows: Youtube: https://www.youtube.com/@tallmanrobotics Tiktok: https://www.tiktok.com/@tallmanrobotics Facebook: https://www.facebook.com/tallmanroboticslimited
Linkedin: https://www.linkedin.com/in/tallman-robotics