Heavy Duty Circular Conveyor

Heavy Duty Circular Conveyor: A High Payload Track System with a Load-Bearing Support Table

Author: ShanGong, Director of Engineering Department | September 2026 | Category: Circular Conveyor Systems

A standard circular conveyor is built around one assumption: whatever sits on the carriage, the guideway carries it. That holds for electronics, small assemblies and light fixtures. It stops holding when each carriage carries a 50 kg fixture, and it fails outright when a station presses down on the part with several hundred kilograms of process force.

This heavy duty circular conveyor was built for exactly that duty: ten carriages around a rectangular loop, 50 kg per carriage, and up to 500 kg of top-down load at every station. The design answer is a high payload track system with two load paths: the V-type guideway moves and locates the carriages, while a single-piece support table beneath the fixture plates takes the weight and the station force. The page below walks through how that system is configured, what each part is responsible for, and what we need from you to build one for your line.

Heavy duty circular conveyor: ten positioned stations on a rectangular V50 loop, built on an enclosed cabinet base.

Key Specifications of this Heavy Duty Circular Conveyor

Main components of the high payload track system.

Why a Heavy Duty Circular Conveyor Needs Two Load Paths

In a conventional loop, every force on the carriage travels through the conveyor slide, its rollers and the guideway. Sizing the guideway for the heaviest moment in the cycle, which is usually a press, insertion or sealing stroke rather than the weight of the part, drives the rail, rollers and arcs up in size and cost, and still leaves the rollers absorbing shock loads they are not designed for.

This system separates the two jobs:

• The guideway carries motion. The conveyor slide on the V50 guideway steers the carriage around the loop and gives the positioning unit a repeatable reference. It carries the carriage in travel, not the process force.
• The support table carries force. Each fixture plate runs on eight ball transfer units that roll on a continuous, 90 mm-thick fixture support plate. When a carriage stops and a station presses down with up to 500 kg, the force passes from the plate through the balls into the support plate and machine frame. None of it has to go through the guideway.

Figure: The two load paths in this high payload track system. Schematic, not to scale.

The result is a loop that keeps the positioning behaviour of a precision circular conveyor while handling fixtures and process forces normally reserved for a heavy rotary index table or a pallet transfer system.

System Configuration of this Heavy Duty Circular Conveyor System

The conveyor in this project is ordered as TMX01-V50-S612R90-Y1016-10LD10-L3812-L617-C20. Read left to right, the code describes the whole loop:

A rectangular layout was chosen over an oval because it gives two long, straight working runs of four stations each, plus a straight station on each short side. No station sits in an arc, so every carriage is positioned on a straight, where the guideway reference is best.

Why the station pitch is 1,016 mm

On a chain-driven loop, each carriage is fixed to the chain at a pin, so the distance between carriages can only be a whole number of chain pitches. 20A chain has a 31.75 mm pitch, and a nominal 1,000 mm spacing works out to 31.5 pitches, which no chain can deliver: carriages would have to alternate between 31 and 32 pitches, and alternate stations would stop about 16 mm off their nominal position after every index. That is far outside the capture range of any positioning unit.

The loop is therefore built on 32 pitches per carriage, a station pitch of 1,016 mm, and closes exactly:

Plan view: four stations on each long side, one at the middle of each short side.

With this geometry the stations fall symmetrically: the four long-side stations sit at ±508 mm and ±1,524 mm from the loop centre, and the short-side station falls exactly at the middle of each end. The chain distance from the last long-side station, around the corner to the end station, is one full pitch.

Load-Bearing Support Table and Ball Transfer Deck

The support table is the part of a heavy duty circular conveyor that is easiest to get wrong, and two details decide whether it works for years or wears out the ball transfer units within months.

Section through the station: the fixture plate’s ball transfer units roll on a 90 mm-thick support plate that takes the station load.

A fixture plate at a station: the slide rides the V50 guideway while the ball transfer units bear on the support deck alongside it.

One continuous plate under the ball path

Ball transfer units tolerate a smooth surface indefinitely, but every joint, step or gap they roll over is a small impact on the main ball and its support balls. Over millions of passes those impacts are what shorten their life. The fixture support deck is therefore machined as single plates along the whole ball path, so the balls never cross a seam in travel.

Support all the way round the arcs

On a straight run, the ball transfer units under a 560 mm-long fixture plate follow narrow, parallel tracks. In an arc, the plate rotates as it moves and its corners sweep outward, so the balls trace a wider band than they do on the straights. The deck is shaped to that swept envelope, which keeps every ball supported from below through each corner, not just on the working runs.

A fixture plate entering a corner. The circled ball transfer units swing outward in the arc, so the deck has to extend under their full swept path.

Rolling resistance is part of the drive sizing

Running 50 kg carriages on ball transfer units adds rolling friction to every move. That load, together with the mass of ten loaded carriages, sets the drive: a 3 kW servo motor through a TM-PGR115 precision helical planetary reducer turns the chain. We size the drive for the full loaded loop, including the ball rolling resistance, rather than for the guideway alone.

Positioning at Every Station in this Heavy Duty Circular Conveyor

A chain loop on its own indexes the carriages to about ±0.5 mm, which is fine for transport but not for pressing, sealing or testing. Every one of the ten stations in this build carries an LD direct-lift positioning unit. A pneumatic cylinder drives a guided lifting plate straight up; a cam follower at its top engages a locating notch on the carriage and centres it along the track, while the V guideway holds its radial and vertical position. When the station has finished, the unit drops clear and the carriage is released to index.

LD direct-lift positioning unit (green) beneath a conveyor slide, shown with the fixture plate removed.

With a chain drive and a positioning mechanism, the repeat positioning accuracy at each station is ±0.03 mm, against a project specification of ±0.05 mm. For comparison, a timing belt loop with positioning repeats to ±0.05 mm. The positioning unit also takes the carriage off the chain’s own tolerance: the chain only has to bring the carriage within capture range, and the positioning unit does the final location.

The straight up-and-down motion matters in a heavy duty loop for a practical reason. Ball transfer units, fixture brackets and the positioning hardware all share the space under the fixture plate. A unit that rises into engagement and drops fully clear keeps the travel envelope free, where a rotating arm would sweep into the path of the ball transfer units.

Drive, Controls and Cycle Time

The loop is driven by a single 20A roller chain running around a 41-tooth sprocket at each of the four corners, with one driven sprocket and tension blocks at the others. Chain was specified over timing belt for this duty because it transmits the higher drive force of a heavily loaded loop and gives the better positioned accuracy.

Corner of the loop: the chain wraps a corner sprocket inside the 612 mm V50 arc, with the fixture plates running round on the outside.

Motion control runs on a Trio MC405 motion controller with a 10.1-inch Trio touch-screen HMI. The HMI and controller program are delivered in English, and the HMI displays controller data and servo monitoring without separate HMI software. The 3 kW Delta servo motor is powered from its matching servo drive, and proximity sensors confirm carriage presence and home position.

Cycle time for this build

The line indexes one station every 5 seconds. With about 0.4 s allowed for the positioning unit to engage, the carriage has roughly 4.6 s to travel 1,016 mm, an average of about 0.22 m/s. On a symmetrical trapezoidal profile (one third accelerating, one third at speed, one third braking) the peak speed is about 0.33 m/s. That is deliberately gentle: at 50 kg per carriage, a moderate speed keeps acceleration forces on the chain, the fixtures and the parts low. Because every carriage moves one station per index, the line completes one part every 5 seconds, or up to 720 parts per hour.

For the general method behind these figures, see the conveyor cycle time calculation guide linked below.

Engineered Through 3D Design Review

A high payload track system is rarely a catalogue item. It has to fit around the customer’s own process equipment, and the details only become clear when both sides are working on the same model. On this project the conveyor was developed inside the customer’s full cell layout, with several review rounds before release:

• Requirement form first. Carriage count, positioned stations, pitch, index time, plate size, payload, downward force and environment were fixed on our technical requirement form before any design work started.
• Positioning changed from rotary to direct-lift. The first model located the carriages with a rotating arm. The customer asked for up-and-down positioning at all ten stations, and the LD direct-lift unit replaced it.

First-round model with the rotary positioning arm, marked up by the customer for up-and-down positioning at every station.

• Support structure added for 500 kg per station. The table and supporting structure were added to the conveyor scope so each station could take top-down process load independently of the guideway.
• Interference cleared. The table was reshaped where it clashed with the customer’s process machines, and clearance was opened between the ball transfer units and the positioning hardware along the travel path.

Review markups: table legs clashing with a process machine (left) and a ball transfer unit passing too close to the positioning hardware (right).

• Deck detail confirmed. Joints in the support path were removed so the ball path runs on single plates, and full support through the corner arcs was confirmed in the final review.

Support path joints highlighted in review; the ball path was changed to continuous plates.

At handover we supply the conveyor 3D model and electrical drawings in English, so the loop can be integrated into your own machine documentation.

Machine Frame of this

The loop, support deck and drive sit on a welded frame with an approximately 4,950 × 1,760 mm top plate, closed in with sheet-metal panels and lockable doors, and recessed on one side where an adjacent process machine stands close to the loop. The enclosed base houses the drive and electrical equipment and stands on levelling feet with castors for positioning during installation.

Front elevation: three double-door bays, levelling feet and castors.

Rear view: the base is recessed on one side to make room for an adjacent process machine.

Applications of this Heavy Duty Circular Conveyor

The conveyor loop at the centre of the customer’s assembly cell, with process machines and feeders arranged around it (customer layout model).

This build serves a multi-station consumer products assembly line, where the stations include film sealing, cutting and leak testing on heavy fixtures. The same heavy duty circular conveyor arrangement suits any process where the fixture is heavy or the station pushes hard on the part, including:

• Press-fit, riveting and staking stations on automotive sub-assemblies
• Heat sealing, crimping and membrane or film application
• Battery module and pack assembly with heavy nests
• Leak, pressure and functional testing where the fixture clamps the part
• Screw-driving and assembly lines using large multi-part fixtures

Options for your Custom Heavy Duty Circular Conveyor

• Bellows covers on the conveyor slides to keep water, oil, dust and liquids off the guideway
• 316 stainless
• guideway for washdown and corrosive environments
• Custom fixture plates and support structures to your part, or built to your own fixture drawings
• Timing belt drive where quieter running matters more than drive force (±0.05 mm with positioning)
• Export packing in plywood crates for long-distance shipment

What We Need to Quote Your Heavy Duty Circular Conveyor

The fastest way to a quotation is to send the same data our requirement form asks for. For a high payload track system, the two items that matter most are the ones most often left blank: the downward force at each station and the size of the fixture plate.

Every system carries a one-year warranty covering quality defects.

Frequently Asked Questions

How much can each carriage of a heavy duty circular conveyor carry?

This build carries 50 kg per carriage. Where the payload or fixture size goes beyond what the guideway should carry alone, the fixture plate is supported on ball transfer units running on a support table, so carriage payload is no longer limited by the conveyor slide rating.

Can a press or sealing station sit directly on the loop?

Yes. With a load-bearing support table, the station force goes from the fixture plate through the ball transfer units into the table and frame. This build takes up to 500 kg top-down at every station without loading the guideway.

Can I have exactly 1,000 mm between stations on a chain-driven loop?

Not with standard roller chain. Carriages attach at chain pins, so the pitch has to be a whole number of chain pitches, and no standard chain pitch divides 1,000 mm evenly. We choose the nearest workable pitch, 1,016 mm on 20A chain in this build, and lay out the stations around it.

Is chain or belt drive better for a high payload track system?

Chain is the usual choice for heavy loads: it carries higher drive force and, with a positioning mechanism, repeats to ±0.03 mm. Belt drive is quieter and repeats to ±0.05 mm with positioning. Either drive without a positioning mechanism repeats to about ±0.5 mm.

Do the ball transfer units stay supported in the corners?

They must. A fixture plate sweeps a wider path through an arc than on a straight, so the support deck is shaped to the full swept envelope and machined as continuous plates, which keeps every ball supported and avoids seams that shorten ball life.

Related Pages

• Circular Conveyor Systems
• Precision Circular Conveyor System
• Vertical Mounted Double Rail Heavy Load Circular Conveyor Production Line
• Servo Driven Circular Conveyor
• Conveyor slide load calculation (C Motion Technical Guide)
• Circular conveyor positioning accuracy (C Motion Technical Guide)
• Conveyor cycle time calculation (C Motion Technical) 

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