Choosing Capacity for a Block Factory in Syria: Pallets, Cycles and Shift Hours

Choosing capacity for a block factory in Syria is arithmetic before it is commercial. A machine does not make blocks per day. It makes cycles per shift, and each cycle delivers one pallet of mould cavities. Multiply the two, subtract the hours your plant will not actually run, and you have the number you can promise a customer. The QST6-15 shows the shape: six hollow blocks per mould on a 15 to 23 s cycle, quoted at 8,640 to 11,520 hollow blocks in an 8 h shift.

How many blocks does one shift actually make?

Start with seconds. An 8 h shift holds 28,800 s, so a 15 s cycle allows 1,920 cycles and a 23 s cycle 1,252. On the QST6-15 six hollow blocks leave the mould each cycle: 11,520 blocks at the fast end, 7,513 at the slow end, if the machine never stops. The quoted 8,640 to 11,520 is narrower, and the low figure tells you why. It is 1,440 cycles, a 20 s average, not 23 s.

The gap between 1,920 theoretical cycles and 1,440 quoted ones is where a real plant lives: the mould change at the start of a run, the mixer waiting on aggregate, the stacker clearing a jam, the operator checking a corner that is not square. None of that is a fault. It is the shift.

Which derating figure turns cycles into shippable blocks?

Use the hours your plant runs, not the hours on the drawing. Count cycles on your own line for a week, divide by the shifts, and plan on that. If the counter shows 1,440 cycles in 8 h, your effective cycle is 20 s and your planning figure is 8,640 hollow blocks. Every model is quoted on its own dry cycle, so the QST1200 and QST1800 at 15 to 25 s need the same correction before you compare them.

One more subtraction belongs here. A shift does not begin at full cavity count. Moulds are swapped between products, and a plant selling two sizes loses part of every shift to each swap unless it batches orders. Plan the year on the mix. If most of your output is hollow block, the hollow block rate is the rate you size on.

The pallet, not the block, is the unit you buy

Every cycle produces one pallet, so pallet count per shift equals cycle count per shift. That changes what you are pricing. The QST6-15 carries a 980 x 680 x 20 mm pallet, about 0.67 m2 of face. The QST1200 carries 1,350 x 880 x 25 mm, about 1.19 m2. The QST1800 carries 1,400 x 1,400 x 30 mm, about 1.96 m2. A 20 s pace on the smallest machine puts 1,440 pallets in the yard in one shift.

The curing yard is laid out around those pallets: footprint plus aisle, multiplied by the days a block needs before it ships. Three days of cure on 1,440 pallets a shift is 4,320 pallet positions before the cuber clears a layer. The cuber follows the same number. The QS-1200A is rated at about 3,800 pallets per shift and stacks to 1,400 mm, so on a QST6-15 it is not the limit.

Why the block size the market buys changes the machine

Cavity count belongs to the mould, not the machine, and it moves by a factor of five between the two reference products. On the QST6-15 a hollow block mould of 390 x 190 x 190 mm carries 6 pieces. A standard brick mould of 240 x 115 x 51 mm carries 32 to 36. Same press, same shift: 8,640 to 11,520 hollow blocks, or 46,080 to 61,440 bricks.

That rewrites the sizing question. A buyer who needs 8,000 hollow blocks a day needs 1,333 pallets, under the 1,440 pallet pace of the 980 x 680 mm machine, with room to spare. A buyer who needs 60,000 standard bricks a day needs 1,875 pallets at 32 pieces, above that pace and reachable only at the top of the 61,440 rating, with nothing left for a mould change. The second buyer is not buying more blocks. He is buying more pallets per shift, and that pushes him to a 1,350 x 880 mm or 1,400 x 1,400 mm pallet.

Read the mix before the model. If the market takes hollow block for walls and standard brick for infill, both moulds run, and the product with the higher pallet count per shift sets the machine size.

What does the next pallet size cost in yard and handling?

Three things scale with the pallet. Mass: 12 t on the QST6-15, 17 t on the QST1200, 34 t on the QST1800. Installed power: 34.4 kW, 57.6 kW, 104 kW. Vibration force: 68 kN, 150 kN, 280 kN, all at a rated 31.5 MPa except the QST6-15 at 25 MPa. Those numbers decide the foundation, the transformer and the crane on your site.

Then the yard. A 1,400 x 1,400 mm pallet takes nearly three times the footprint of a 980 x 680 mm one, so the same pallet count needs a bigger shed and the same shed holds fewer pallets. Handling has to match. A clamp that lifts 40 hollow blocks or 500 to 800 standard bricks per bite, on a 2,000 kg load, sets the pace the cuber and the yard absorb.

The decision rule: sell first, then size

Pick the capacity from the mix you can sell in the first 12 months, then check that the yard fits the pallet count. Two steps, in that order. Selling capacity you cannot fill puts capital into a 34 t frame that runs four hours a day. Buying below the mix puts a second shift on a machine that cannot carry it.

Run the numbers in this order and the model picks itself:

• List the products you can sell and the monthly volume of each, in pieces.
• Convert each product to pallets per shift by dividing the piece count by the cavities in its mould.
• Add the pallets, add the mould change time, and compare with the 1,440 to 1,920 cycles an 8 h shift gives.
• Multiply the pallet count by the cure days to get the yard positions you need.
• Only then choose between a 980 x 680 mm, a 1,350 x 880 mm and a 1,400 x 1,400 mm pallet.

The last check is the one buyers skip. If the yard cannot hold the pallets a bigger machine makes, the extra cycles stand in a queue and the plant ships what it shipped before, on a heavier frame fed by 104 kW. Send the product list, the daily volume and your yard dimensions, and the arithmetic settles the pallet size.