Bottom line: a smart tool cabinet and a smart parcel locker look like different products, but they are the same engineering problem. Both are a sheet metal body carrying electric locks, a controller and a network link. The tool cabinet manages assets and permissions inside a workshop. The locker manages the relationship between compartments and people in a public place. Get that distinction right and the structure and the specification follow.
In practice, the enquiry usually specifies only how many compartments, what size, and that it must scan a code. The details that decide whether the project runs smoothly are different: what the doors do when power fails, whether the cabinet still opens without a network, how high the base sits under a canopy, and what cycle life the locks are rated for.
1. Two products, two design priorities
- Smart tool cabinet. Used in workshops by operators, managed by a storekeeper. Fewer and larger compartments, a body that survives impact from trolleys, and an audit trail that links each opening to a person or a work order. The cabinet sits on the workshop floor, so door thickness, hinge strength and impact protection matter more than appearance.
- Smart locker. Used in busy public areas with no one on site. High compartment density across the available width, fast opening, clear on-screen interaction, resistance to theft and vandalism, and a defined process for exceptions such as an overstaying user or a wrong compartment. Sheet metal tolerance, door reveal consistency and lock repeatability decide the first impression.
- The common ground. Both are sheet metal plus electronics plus software. The cabinet earns its keep by holding the electronics firmly for years without loosening, leaking or failing. When something does go wrong on site, the complaint is rarely about software. It is a door that does not close properly, a lock that does not engage, or water inside.
2. Modular compartments: design for production and expansion
Compartments repeat, so one drawing per cabinet is a mistake. We build a size series, with the master cabinet carrying the controls and the slave cabinets carrying compartments only, sharing the same uprights and coupling interface.
- Master plus slaves. The master integrates the controller, screen, card reader, power supply and network interface. Slaves extend without limit. Expansion then means adding a slave, with no work on the master. That is the lowest-cost architecture to maintain.
- Thickness and stiffness. Doors are commonly 1.0 to 1.5 mm, uprights and rails 1.0 to 1.2 mm, compartment floors 0.8 to 1.0 mm. Any compartment taller than 400 mm, and any high-traffic compartment, needs a stiffening rib or a formed flange. Without it the door goes wavy and the reveal shows it immediately.
- Reveal and prying resistance. Keep the door reveal between 1.5 and 3 mm and even all round, and form the door edge so that it overlaps the upright. An uneven or oversized gap is both a security weakness and a quality impression.
- Anti-pinch. On any cabinet the public touches, radius or cover the door and compartment edges. Compartments within a child height range deserve particular attention; this is a frequent source of complaints.
- Wiring and connectors. Reserve a vertical cable route in the upright or the back panel, and make each compartment lock and status lead a pluggable module connector. A failed lock is then a module swap instead of a full rewire, which cuts maintenance cost significantly.
- Hinge life. Locker doors cycle constantly, so specify hinges for 100,000 cycles or more. Tool cabinet doors are heavy and wide, so use heavy-duty hinges with a stop to prevent the door sagging onto the sill.
3. Locks: fix the power-loss behaviour first, then pick the type
The usual mistake is choosing on price, then discovering that the power-loss behaviour does not meet the requirement. Decide the failure mode first, then choose the lock within that group on life and cost.
| Lock type | Behaviour on power loss | Life and feedback | Where it fits |
|---|---|---|---|
| Solenoid lock, 12 or 24 V | Releases when power is lost | Around 100,000 cycles, usually no feedback | Tool cabinets and lockers where cost matters and release on power loss is acceptable |
| Electric bolt lock | Releases or stays locked, model dependent | Around 200,000 cycles, some give a door status signal | Compartment doors needing a higher security level |
| Motor lock with gearbox | Stays locked, state is retained | 300,000 cycles or more, integral position feedback | Parcel lockers and unattended retail where every state must be traceable |
| Mechanical lock with electronic key | Independent of power | Long mechanical life, manual record keeping | Sites without reliable power or with simple management |
| Electronic padlock | Usually stays locked on power loss | Dependent on the lock body, often with Bluetooth audit | Retrofit projects and temporary compartment authorisation |
The power-loss strategy belongs in the contract. A public locker is normally configured to release on power loss, or to provide a manual emergency opening, so that people are not trapped and the fire service can act. An asset-control tool cabinet must stay locked, so that cutting the power does not open the whole cabinet. The two requirements are opposites, and having both on one drawing is a safety problem waiting to happen.
4. Controller, communications and power
- Controller and interface. A controller is usually an embedded board or an Android mainboard with a 10 to 21 inch touch screen. Card, code, fingerprint and face recognition are chosen for the user group: staff sites are more reliable with cards, public sites are more universal with a QR code.
- Network architecture. Wired Ethernet is the most reliable uplink, then WiFi, then 4G for mobile installations. Inside the cabinet, the controller talks to compartment boards over an RS485 or CAN bus. Bus addresses must be fixed in hardware, so that a mis-plugged connector cannot open compartment B when A was requested.
- Offline capability. Non-negotiable. The cabinet must keep opening without a network, log locally, and upload when the link returns. The simplest acceptance test is to unplug the network cable for a day.
- Power and backup. Supply the controller and the locks from separate rails. Give the controller a UPS so it can finish the current transaction and flush its data. The lock rail follows the agreed power-loss strategy. Size the power supply for the number of compartments opening simultaneously, not for the total compartment count.
- Safety logic. Automatic closing after a timeout, reminders for items left behind, alarms for abnormal or forced opening, and a log retention period all belong to software. Each one still needs a sensor position in the structure, either a micro switch or an infrared pair.
5. Outdoor and sheltered installations: water paths matter more than the IP number
Outdoor lockers rarely fail because the IP rating was too low. They fail because water arrives from an unexpected direction: driving rain on the side, water returning under the hood, or standing water at the base. Specifying by installation environment is more effective than asking for IP65 in general.
| Installation environment | Enclosure and protection | What gets missed |
|---|---|---|
| Indoor workshop or office | Standard powder coated body, IP20 or better, no canopy | Screen brightness, cable route, floor flatness |
| Sheltered outdoor or lobby | Reinforced sealing around IP54, rain hood, raised base | Driving rain and standing water; an inadequate base fails first |
| Fully exposed outdoor | IP65 sealing, extended sloped hood, drain holes, anti-condensation heater | Internal temperature and screen readability in direct sun, over 60 degrees Celsius in summer |
| High humidity or coastal | Stainless or upgraded coating and hardware, full grounding and surge protection | Hinges and locks corrode first, do not reuse standard zinc plated parts |
6. Installation, base and acceptance
- Base and fixing. Keep the mounting surface flat to within about 2 mm per metre, and anchor the cabinet against tipping with expansion bolts or chemical anchors. For a public-facing unit, anti-tip anchoring is not optional. A cabinet that falls over causes injuries that cost far more than the cabinet.
- Coupling and gaps. Bolt adjacent cabinets together with coupling brackets so they behave as one structure, and keep the gaps even. Cabinets standing on their own feet will drift slightly and the reveals will look ragged within months.
- Cable routing and ergonomics. Separate power and data routes, and keep data cables away from power. Put the centre of the screen between 1.3 and 1.5 metres above the floor, which suits both standing adults and wheelchair users.
- Grounding and protection. Prove body continuity, and fit an RCD and surge protection at the incoming supply. For outdoor units, follow the project design for lightning protection and earthing.
Verify the cabinet against the table below on arrival. The power-loss and network-loss rows must be tested on site, not read from a data sheet:
| Check item | Acceptance criterion | How to test |
|---|---|---|
| Door reveal | Reveal variation within 1 mm per compartment, no visible mismatch | Feeler gauge or visual check on every compartment |
| Lock engagement | Every compartment opens and closes first time, no sticking or noise | Cycle each compartment 20 times |
| Power loss behaviour | Matches the agreed strategy, release or remain locked | Cut mains power and confirm compartment by compartment |
| Network loss behaviour | Cabinet still opens locally and no log entry is lost | Unplug the network cable, open a compartment, check the log |
| Compartment state sensing | Reported state matches reality for every compartment | Place and remove items and verify each state |
| Grounding and RCD | Body grounded and continuity proven, RCD trips on test | Multimeter continuity test, press the RCD test button |
| Screen and card reader | No dead zones on the touch panel, read range as specified | Test angles and distances on site |
| Documentation | Operating instructions, maintenance card and wiring diagram supplied | Check against the packing list |
7. What to put in the enquiry
- Installation environment, indoor, sheltered or exposed, and the local climate, including whether a canopy, heater or dehumidifier is needed.
- Compartment count and size series, what each compartment holds, its maximum weight, and whether cooling, charging or reinforced locking is required.
- Power-loss strategy and emergency unlocking method, and whether fire alarm integration is required.
- Verification method, card, QR code, fingerprint or face, and the interface protocol and fields if the cabinet must connect to an existing platform or MES.
- Screen size and mounting height, plus any requirement for voice prompts or accessibility.
- Colour, branding and graphics, and any corporate identity standard to follow.
- Supply conditions, available single phase capacity and space for a UPS, and network conditions including cable position and signal strength.
8. Frequently asked questions
When the power fails, should the doors open or stay shut?
There is no single answer; it depends on the application. A public locker is normally set to release, or to offer a manual emergency opening, so nobody is trapped. An asset-control tool cabinet must stay locked. Put the requirement in the contract, and test it before shipment rather than relying on a default.
Can the compartment sizes be fully customised?
Yes, but start from the size series. Compartment size is limited by lock installation space, door stiffness and upright spacing. A fully bespoke compartment adds tooling and setup cost and lengthens spare part lead time. Pick the nearest size in the series and adjust locally.
What IP rating does an outdoor smart locker need?
Around IP54 for sheltered positions and around IP65 for exposed ones, but the rating is only the entry ticket. Service life is decided by the hood length and slope, how far the base is raised, where the drain holes sit, and whether anti-condensation measures are fitted.
Does the cabinet still open without a network?
It must. The controller needs an offline strategy, local logging during the outage and catch-up upload afterwards. Test it by pulling the network cable, not by confirming that a setting exists in the menu.
What material and finish should the body use?
Indoor units are typically cold-rolled steel with a powder coat. Sheltered and outdoor units should use an outdoor-grade powder coat at a dry film thickness of about 60 to 80 microns, or galvanised steel with a coat. Coastal sites justify a stainless body or a markedly upgraded coating system, with hinges, locks and fasteners upgraded at the same time.
The touch screen is unreadable in direct sunlight. What fixes it?
Three things together: a high brightness panel around 1,000 candelas per square metre, an anti-glare treatment, and a physical shade in the structure. Also plan for panel cooling and low-temperature heating, otherwise the screen dims in summer and will not start in winter.
9. About Xingyuan Electric
Xingyuan Electric (Suzhou) Co., Ltd. is located in Lili Town, Wujiang District, Suzhou, and manufactures sheet metal cabinets and electrical assemblies. The team is 52 people, the production base covers more than 5,000 square metres, and 20-plus laser cutting, CNC bending and welding machines cover blanking, bending, welding, coating and assembly. Smart tool cabinets, smart lockers, chemical cabinets, server cabinets and Rittal-style cabinets are all built to drawing or sample, with modular compartment design and support for lock, wiring and controller integration. Standard lead time is 7 to 15 days.