If you are buying a custom parcel sorting system, the first question is not which vendor to call — it is what you are asking the machine to do. A sorting system is specified by numbers, and every number you leave undefined is a number the vendor will fill in with an assumption that favours their standard product. This guide walks through the decisions in the order an integrator will ask for them, so you can arrive with a specification instead of a wish.
A custom parcel sorting system is an automated line that identifies inbound parcels and diverts each one to a defined destination — a chute, a tote, a palletising cell or an outbound lane — without an operator touching the item. It combines induction, identification, a sorting mechanism, destination hardware and controls into one integrated line. A reference design and specification framework for parcel sorting systems is documented at truelisort.com/solution/, which is a useful baseline when you compare what your own operation actually needs.
Throughput is measured in parcels per hour (pph) at the sorting mechanism, not at induction, because induction is where throughput is usually lost. Specify three numbers, not one: your average daily volume, your peak hour volume, and the maximum you want the line to absorb during promotions. A line sized to the peak-hour figure is expensive; a line sized to the daily average will collapse in the week you need it most. The honest answer is to size the mechanism for the peak hour and use a buffer conveyor to absorb the difference.
The mechanism is chosen from the item profile, and choosing the wrong one is the most expensive mistake in the project. The comparison below reflects how integrators match mechanisms to profiles.
| Mechanism | Best for | Typical envelope | Watch out for |
|---|---|---|---|
| Shoe sorter / sliding-shoe sorter | Stable cartons and totes at high rate | Up to ~12,000 pph | Soft or overstuffed bags can be misdischarged |
| Cross-belt sorter | Mixed shapes, polybags, small items | Up to ~15,000 pph | Higher cost and more carrier points to maintain |
| Bomb-bay / tilt-tray sorter | Medium-rate, mixed freight | 2,000–6,000 pph | Gravity discharge needs vertical space |
| Pusher / diverter arm | Low rate, heavy cartons | Under ~2,000 pph | Contact force can damage light packaging |
If your mix includes polybags, envelopes and irregular soft packaging alongside cartons, a cross-belt or a combination line is usually the honest recommendation. If you ship stable cartons and totes at high rate, a shoe sorter is the efficient choice. The decision is driven by your item profile, and the specification should state the profile in millimetres and grams, not in adjectives.
Chute count is the second cost driver after mechanism, and buyers routinely overspecify it. The number of chutes should equal your number of simultaneous live destinations plus a small buffer — not the number of postcodes you ship to. Routing granularity comes from the software and the labelling, not from physical chutes. A line with 24 chutes and a warehouse that ships to 9 provinces will run with most chutes idle, which is capital spent on steel you never use. Detailed guidance on destination planning is available from truelisort.com/product/.
Specify the identification method the system will use to make its divert decision: barcode (1D/2D), RFID, volume/weight dimensioning, or a camera-based character-reading system. For parcel operations, a six-sided barcode scan array plus a dimensioning tunnel is the practical baseline. Then specify the data layer: the system must receive a sort plan from your WMS or OMS and return a completion record, and it should do so through a documented API rather than a file drop. Put the API contract in the specification, including the fields, the retry behaviour and the failure handling, because that is where integration projects fail.
Ask for a control architecture built on a PLC with a documented safety circuit, and ask which safety standard the line is designed to. For European deliveries, the machinery directive and the relevant EN ISO 13849 performance levels apply; for other markets, the integrator should state the equivalent. Emergency stop coverage, guard interlocks, light curtains at induction and lockable isolation are the items to check on the drawing before the factory starts cutting steel. A safety review after the line is built is a negotiation; a safety review before is a design change.
Compare quotations line by line, on the same quantities. The table below lists the categories that should appear, so you can spot what a vendor has left out.
| Quotation line | What it should cover | Common omission |
|---|---|---|
| Sorting mechanism | The carrier, drive and belt/carrier wear parts | Wear-part lifecycle and cost per million parcels |
| Induction | Singulation, gap control and the scan array | Gap-control tuning at your real item mix |
| Destinations | Chutes, trays and end-of-line hardware | Chute capacity for your tallest carton |
| Controls and software | PLC, SCADA, sort-plan interface and licences | Annual software maintenance and support terms |
| Installation and commissioning | Mechanical, electrical, integration and acceptance test | Acceptance test criteria and the re-test procedure |
| Training and spares | Operator training and the recommended spares list | On-site response time and spare-part lead time |
A quotation that is 20% cheaper because three of these lines are missing is not cheaper. Ask for the lifecycle cost over five years, including wear parts, energy and the expected maintenance hours.
For a configured line from an established manufacturer, expect roughly 8 to 16 weeks from order to acceptance, with the longest items being the sorting mechanism manufacture and the site preparation. A fully bespoke design can take longer. Build the site-readiness work into your project plan, not into the vendor's.
Yes, and it usually should. Specify returns handling in the original specification, because it changes the induction station and the identification requirement. Retrofitting returns onto an outbound-only line is possible but rarely elegant.
Below roughly 2,000–3,000 parcels a day, manual sorting with a scanner and a put-wall is usually the better economic answer. Above that, the labour cost and the error rate of manual sorting start to dominate, and automation pays back within a few years. The exact number depends on your labour cost and shift pattern.
A custom parcel sorting system is specified by the item profile, the peak-hour throughput, the destination count and the data integration — in that order of cost impact. Bring those four numbers, plus a chute capacity drawing and an API expectation, and you will get quotations that are comparable. Bring a description of your problem, and you will get three different machines that each solve a slightly different one.
For background on the machinery safety requirements that apply to conveyor and sorting lines, see the machinery directive summary at en.wikipedia.org/wiki/Machinery_Directive and the safety-of-machinery standard overview at iso.org/standard/53833.html. For the sort-plan data integration side, the OPC UA interoperability specification at opcfoundation.org is the usual reference for control-layer communication.