Magazine racks for carriers, pallets and fixtures

Catalogs describe a magazine rack as board storage. On a real floor it ends up holding carriers, test pallets and fixtures, because that is what actually moves between stations once a board is populated. The rack does not care what sits in the slot. Four numbers decide whether it works.

Slot width comes first

A bare board is one to two millimetres. A carrier plate with a board latched to it is several, and the number that matters is the thickest point, not the plate. Measure over the standoffs, the latches and anything proud of the surface.

• Gear-track and screw racks: 5 mm wide, 3.5 mm deep. Fine for thin carriers and panel frames.
• Belt racks: 5 mm wide, 4 mm deep. The deeper slot holds a heavier plate more securely.
• All-aluminum HT racks: 7.5 mm wide. Built for thicker, warped or populated boards, which is the same problem a carrier presents.

If the carrier does not drop into the slot under its own weight, it is the wrong slot. Forcing it is how edges get chipped.

Payload is the number nobody publishes

Bare boards weigh almost nothing, so the question never comes up. Carriers change that. A rack on the aluminum pillar and galvanized steel frame carries up to 85 kg (187 lb). The all-plastic chassis carries up to 50 kg (110 lb).

That figure is the whole load in the rack, not the load per slot. Worked through: 50 carrier plates at 1 kg each is 50 kg, comfortably inside the 85 kg frame. Spread the weight evenly across the slots rather than loading one end.

What touches the carrier

Standard racks carry conductive PPE side panels, the usual choice for bare boards. Anodized aluminum carriers sitting on PPE is ordinary practice and works.

If you want no polymer in the load path at all, the HT version of the same chassis replaces every panel with clear anodized aluminum. Anodized then rides on anodized, hard oxide against hard oxide, instead of anodized against bare metal, which is the pairing that actually transfers material. The panels stay conductive, 10⁴ ohms, so the ESD story doesn't change.

Temperature, if the fixture goes through a process

A carrier that rides through a bake or a cure takes the rack with it. The rating has to cover the process, not the storeroom: 80 C for handling and transport, 120 C for warm drying, 200 C for J-STD-033 bake and conformal-coat cure, 300 C for the all-aluminum rack that goes near lead-free reflow.

Width adjustment still applies

Carriers are usually one size, which suits the screw racks: set the width once and it stays through vibration. If carrier sizes change between programs, the gear track adjusts from 50 to 250 mm with both walls moving together, and the belt racks run continuously from 10 mm with no steps.

Before you order

• Thickest point of the carrier against slot width, 5 mm or 7.5 mm.
• Total loaded weight against 85 kg, or 50 kg on the all-plastic chassis.
• Panel material against what the carrier is made of.
• Temperature rating against the hottest step the carrier sees.
• Carrier footprint against the 355 by 250 mm board envelope.
• Loader interface if the rack feeds a machine: 563 mm chassis height, 10 mm slot pitch.

Send us the carrier's length, width and thickness, and we will check them against the slot before you buy. Ask a question, see the magazine racks, or start with how to size a rack to your boards.