Do You Still Need Conveyor? What Robots Replace, and Where Conveyor Still Wins

Munro Footwear Group in Melbourne picks from 5,239 shelf pods using 205 Mushiny robots on a conveyor-free shelf-to-person system. Likewize in Sydney does it differently. Repair jobs arrive on a buffer conveyor, robots deliver the totes to the repair benches, and two outbound conveyors take the finished work away. Both sites are on Mushiny's reference sites page, and both are right for their operation.

That is the honest answer to "do you still need conveyor?" Sometimes you do, and the real question is how much, and where. This article splits the work conveyor does into its separate jobs, shows what replaces each one, and says plainly where conveyor is still the better tool. If you already know you want robots that bring stock to the picker, start with shelf-to-person.

What is conveyor actually good at?

Conveyor moves a lot of the same thing along a fixed path, continuously. That is a narrow job and it does it very well.

For thirty years it was the default answer because it was the only way to move product without a person carrying it. Where volume is high, stable and the path never changes, conveyor is still hard to beat. If you push the same cartons from the same dock to the same despatch lane all day, a robot fleet adds cost and decides nothing that a belt does not already decide for free.

We are not going to tell you conveyor is obsolete, because it is not. It keeps the high-volume, fixed and buffering work. What robots take is the variable routing between zones, and that is where most of the cost and most of the inflexibility sit.

What does conveyor cost you?

Conveyor buys throughput by spending flexibility and floor.

It is installed into the building. Change the flow and you change the steel. A new pick zone, a moved pack bench or a new product family means moving or adding runs, and the layout you commission is the layout you live with.

It takes floor that stores nothing. A conveyor line is a strip of floor that holds product only in transit. It also needs clearance above and around it for access and safety, and a run across an aisle can block a forklift route or force a crossing to be built.

A stoppage stops everything downstream. A conveyor is one connected path. When a section stops, everything fed by it stops too, and a jam at one point can idle work that had nothing to do with the cause.

What jobs does conveyor do, and what replaces each one?

Conveyor is one machine doing four jobs. They can be separated, and each can be replaced on its own terms.

How do robots replace transport between zones?

A robot carries a pod or a tote directly from where it is stored to where it is needed. There is no belt between the two points.

In Mushiny's shelf-to-person system, a robot drives under a shelf pod, lifts it and carries it to the picker. The pod stands up to 2.7 metres and holds small items and bulky ones together. In MIX 4.0, the robot carries a pod of totes to a workstation that presents up to 240 totes an hour. In MIX Pro, tote transfer robots carry totes from the gantry to the workstation at ground level.

The difference from conveyor is that each robot is its own path. The robots work as a swarm, so if one is charging or being repaired, the others keep going. The shelf-to-person system has no conveyor in it and no single point of failure.

Mushiny's grid robots read QR markers on the floor and know where they are to the millimetre. The marker says where the robot is, not where to go. Each robot still chooses its own route across the grid and negotiates with the robots around it. This works because the grid is fenced and people stay outside it, which is also why QR navigation is faster, cheaper and more accurate than SLAM, the mapping method used by robots that share space with people. For the full comparison, see what an AMR is.

How does a grid replace accumulation and buffering?

Conveyor buffers in a line. Product queues along the belt until the next step is ready, and the queue is made of floor.

A grid buffers in storage. Stock that is waiting is stock that is stored, on pods or in totes, and it takes the place it would have taken anyway. At the workstation, MIX 4.0 holds 36 buffer locations for hot items beside the operator and runs two queuing positions and two picking positions, so the picker does not wait for the next pod to arrive.

How does robotic sortation compare with a long conveyor sorter?

This is where the case is strongest, because sortation is the job people most often assume needs a long machine.

A conveyor sorter carries items along a line and diverts each one to a chute. The size of the line sets the number of destinations, so more destinations means more floor and more length. Mushiny's sorters split the batch into orders without that line.

Above the MAX in the same range, the Multi runs 30,000 items an hour or more.

The MAX sorts vertically and horizontally at once, so the destination wall is a grid, not a line. Mushiny puts the floor saving at up to 50 per cent less than a cross-belt sorter. On the MAX, linear-motor carts run on a 0.5 metre pitch, and the destination count follows the machine length.

Two points should stay in view. First, a sorter is still a fixed machine. It is not a robot fleet. What changes is the shape of the footprint and how many destinations fit in it. Second, a sorter takes height as well as floor. Ask for both numbers from any supplier, because 2,700 mm of height is a fact about the building before it is a fact about the machine.

How do robots handle induction and the packing feed?

On a conveyor line the product travels to the operator, and the operator stands at a fixed point on the line. In a goods-to-person system the product still comes to the operator, but a robot brings it to a fixed station instead of a belt.

The picker stays put and the pod arrives. Half of a picker's time in a manual warehouse goes on non-productive walking, and a fixed station removes it. At a sorter, the operator scans an item at an induction port and places it on the machine.

Downstream, an automated bagging machine such as the PolyPacker prints and applies the label, opens the bag, seals the order and sends it on, at up to 1,500 bags an hour. It conveys the finished bag onward itself, and that is a good example of the kind of short conveyor run most sites keep.

Where does conveyor still win?

Three places.

Very high stable volume on one path. If the same large flow runs from A to B all day and will keep doing so, a belt is simple, proven and hard to beat. You would be paying for flexibility you never use.

Heavy or oversized items. Both Mushiny sorters have limits. The Minisorter handles items from 50 x 50 x 5 mm to 750 x 500 x 250 mm, at 0.02 to 10 kg depending on size class. The MAX handles 50 x 50 x 1 mm to 450 x 320 x 320 mm, at 0.02 to 7 kg. Anything outside that envelope needs another way to move.

The short runs inside a packing line. A few metres of belt between a packing station and a despatch point costs little, takes little floor and does one job well. You will probably keep it, and you should.

How much conveyor will you end up with?

Most sites end up with some. The usual pattern is a short run at despatch and not much else.

Likewize, above, is the example: conveyor at both ends and robots in the middle.

So the question is not "conveyor or robots". It is how much conveyor, and where. A practical way to answer it is to ask four things of each run you have today.

1. Does the path ever change? If it has not moved in years and will not, conveyor is a fair choice.
2. Is it carrying one thing in high volume, or many things in mixed volumes? Mixed work favours robots.
3. What does it stop when it stops? If a single fault idles the whole building, price that in.
4. What is the floor under it worth? A run that stores nothing is floor you are not using for stock.

Bring the answers to the Chatswood Tech Centre. It is the only place in Australia with Mushiny's full range running live under one roof. You can run your own product through it, and it is free to visit.

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