Block Machine for Sale in Riyadh: Pallets, Moulds and Spare Stock

A block machine for sale in Riyadh is quoted as a frame, a mould set and a weight. The parts that decide whether the plant still earns in year five are the pallet fleet under the machine, the mould inside it and the spares on the shelf. A QST1800 at 34 t and 280 kN of vibration force will outrun a smaller machine and still lose a shift when it runs out of boards.

The usual order is backwards. The machine, the mixer and the cuber arrive in one quotation, and pallets and moulds get left for later. Yet they are what turn a 15 to 25 second cycle into saleable block, and the spare kit is what keeps that cycle turning when a limit switch fails mid-shift.

How many pallets does a block plant actually need?

Count boards in five places, not one: inside the machine and the feed magazine, carrying green product to the curing area, standing in the curing racks, in the yard under cured stacks, and the damaged ones pulled out of service. Only the first appears in the machine specification. The rest are the plant.

Two figures set the pace. A QS-1200 pallet feeder returns an empty board on a cycle of about 13 seconds and holds three stacks in its magazine, while a QS-1200A cuber clears about 3,800 pallets per shift at 15 to 18 seconds per layer. Curing time and yard area limit the fleet, not the press.

Board size follows the frame, from 980 x 860 x 22 mm on a QST8-15 and 1,350 x 880 x 25 mm on a QST1200 to 1,400 x 1,400 x 30 mm on a QST1800. Order the whole fleet with the machine, in one size, from one tool. A mixed fleet of near sizes leaves boards that fit nothing.

• In the machine and magazine: boards under the press and the stack the feeder holds, checked for edge damage each shift.
• In transit: boards on the conveyor and the transfer car, the group dropped and chipped most.
• In the curing area: boards holding green block while it sets, the largest group.
• In the yard: boards under cured stacks waiting for the truck or the clamp, exposed to sun and forklift tynes.
• Out of service: cracked, dished or edge-damaged boards, counted as the reorder signal.

Pallet material and thickness decide block tolerance

Two boards of the same footprint are not interchangeable. Thickness sets how far a board deflects under a 280 kN vibration stroke, so a 20 mm, a 25 mm and a 30 mm board carry different loads over the same span. A thin board under a heavy stack puts the block face out of flat.

A steel board holds tolerance and survives the cuber, a timber board is gentler on green product but moves with moisture, and a plastic-faced board is only as good as its core. Three checks belong at goods-in: thickness at the four corners, flatness on the diagonal, and the edge that locates the board. A rounded edge lets the board shift, and every block on it inherits the shift.

Rejects belong in the fleet. A board that has lost an edge, cracked a corner or gone out of flat leaves the machine on the shift it is found, and the count of pulled boards is the reorder signal. A damaged board costs tolerance on every later cycle.

What does mould wear look like before a block fails?

A mould does not fail suddenly. It leaves dimension slowly: the cavity edge rounds over, the base plate polishes and then dishes, and the guiding assembly develops play that shows as a step on the block face.

Moulds in the QS1500 class are wear-resistant alloy steel, CNC machined to micron level and hardened, built from mould frame, core, base plate, guiding assembly and positioning mechanism as separate parts. A scored core or a dished base plate is a part change, not a new mould, and a rounded cavity edge can sometimes be re-machined if the block height still sits inside the drawing.

Product mix decides mould life more than hours do. A QST6-15 mould returns 6 hollow blocks, 32 to 36 standard bricks or 21 to 24 coloured floor tiles per stroke, while a QS1500 press returns 87 standard bricks. More pieces per stroke means more cavity edges to wear, and abrasive sand wears them all faster.

Wear parts to stock, by position

Stock by position, not by catalogue page. Five places stop a line: the feed box, the vibration bearings, the hydraulic seals, the limit switches and the belt, each on its own clock. The feed box wears where mix slides, the bearings live under 3,800 to 4,500 vibrations per minute and a 280 kN stroke, the seals see 31.5 MPa and die of heat, switches die of dust, and a belt fails at the splice.

• Feed box: lip plate, liner set and gate edge.
• Vibration bearings: a full set for the exciter, not one bearing; a line stopped for one waits for the rest.
• Hydraulic seals: one kit per cylinder bore size, sealed and labelled with the part number.
• Limit switches: two of every part number fitted, since a substituted switch changes cycle timing.
• Belt: splice material, a spare roller and the fasteners for the tail drum.

Order the first spare kit with the machine

The cheapest moment to buy a spare is while the machine is being built: it ships in the same crate, on the same documents, and sits on site before the first failure. Put the first kit on the machine order: feed box lip and liners, a full vibration bearing set, a seal kit per cylinder bore size, limit switches matching the fitted part numbers, belt splice material, plus one base plate and one core.

Keep the kit sealed and labelled by position with the part number from the manual. Log every failure by position and hours, and after a year that log tells you what to stock twice.

How do you plan changeover and maintenance into the shift?

A mould change and a pallet change are product decisions, not emergencies, and both can sit inside the shift plan. Run one mould for a full campaign, then change mould, pallet setting and feed box lip in the same stop, while the machine is open.

Use the cycle as the planning unit. A 13 to 18 second cycle on a QSMT1000 and a 15 to 25 second cycle on a QST1200 leave different slack, and the slower machine has less room for an unplanned stop. Put the daily check at the start of the shift: board thickness, mould face, hydraulic level, limit switch function, belt tracking.

Staffing decides how much of this is realistic. A curing line of the QSRGY type runs the whole production task with 3 to 4 persons, a QSGW line with 3 to 6. A crew already at the low end needs the maintenance window as a scheduled stop.

Write the changeover down. Mould number, pallet size, feed box setting and cycle time for each product belong on a sheet at the machine, not in one fitter's head.