QST1500 Block Making Machine Price: What the Model Buys

QST1500 block making machine price is settled on the specification sheet long before any negotiation, because QST1500 is a model rather than a class of machine. The published sheet lists 11,500 x 4,500 x 2,800 mm overall, 20 t of machine weight, a 1,350 x 1,150 x 30 mm tray, 3,800 to 4,500 vibration cycles and forming by vibration with hydraulic pressurization. An offer that gives you a number without those five lines is an offer for a different machine.

That is the whole argument on this page. Each line of the sheet translates into a cost inside the machine: steel in the frame, area on the tray, force in the vibrator, and control quality in the hydraulic and electrical package. Read them in that order and the gap between two offers stops being a mystery and becomes a list of decisions you can accept or refuse.

The 20 t frame is a vibration specification

Machine weight is the first line to read, and the first line a cheap offer trims. A block machine forms by driving a mould and a mix at high frequency, and the frame has to absorb the reaction so the energy lands in the concrete instead of moving the machine across the floor. At 20 t the QST1500 sits between the 17 t QST1200 and the 34 t QST1800, and that order tracks the vibration force each frame is asked to hold: 150 kN, 220 kN and 280 kN.

The effect of a light frame shows up at the mould. Amplitude drops, so the operator lengthens the cycle or lifts the frequency to recover density, and both are paid on every cycle of every shift. It also shows in the columns that carry 31.5 MPa of clamping pressure. A thinner section deflects under load, the mould leaves square, and block height drifts from one end of the tray to the other. Ask for weight in tonnes and force in kN on the same sheet.

What does the 1,350 x 1,150 mm tray decide?

Tray size fixes how many cavities fit, so it fixes pieces per cycle, and it fixes how many boards the plant has to own. The QST1500 runs 1,350 x 1,150 x 30 mm, the QST1200 runs 1,350 x 880 x 25 mm, the QST1000 runs 1,100 x 880 x 25 mm, and the QST1800 runs 1,400 x 1,400 x 30 mm. The extra 270 mm of width on the QST1500 tray is usually one more row of units on a standard layout, paid once in steel and recovered on every cycle.

Thickness is the quieter half of the same decision. A 30 mm board holds flat through years of vibration, and a 25 mm board on a smaller machine is built to a lighter duty. A tray that bows in the middle produces blocks of uneven height, and uneven height is what the cuber grips badly and the customer rejects. Then count boards. At 15 to 23 seconds a cycle the press completes 240 down to 156 cycles an hour, so one shift handles 1,920 down to 1,252 trays. Every tray on the machine is a tray not in curing, so a larger tray earns its cost twice.

3,800 to 4,500 cycles: frequency against force

Frequency is the figure buyers quote, and force is the figure they forget. The QST1500 runs 3,800 to 4,500 vibration cycles with 220 kN of vibration force. The QST1200 covers the same frequency band at 150 kN, and the QST1000 at 105 kN. Equal cycles per minute at lower force means a thinner compacted column and a weaker face layer, which is how thin-walled hollow blocks and pavers arrive with soft corners and a face that changes from tray to tray.

Push a light machine to the top of the band and you get noise rather than density: the frame moves, the surface closes, and the core stays loose. On the QST1500 the sheet pairs 4,500 cycles with 220 kN, and that pairing is the part a lower offer cannot demonstrate, because it has no force figure to print.

Where does the QST1800 stop being the same machine?

The QST1800 is not a QST1500 with a larger badge. It carries 34 t against 20 t, 280 kN against 220 kN, 104 kW installed against 69.1 kW, and 15,500 x 5,500 x 3,200 mm against 11,500 x 4,500 x 2,800 mm. Its tray is 1,400 x 1,400 x 30 mm on a 15 to 25 second cycle. Published output is up to 220,000 standard bricks in an 8-hour shift, against up to 120,960 for the QST1200 on its 1,350 x 880 mm tray.

That last pair is the decision. The extra tonnage and force hold density on a bigger tray, but the tray then sizes the plant around it: a wider cuber, more boards in circulation, a mixer that can feed the machine without waiting, and a yard that can take the stack. A QST1800 bought for a plant built around QST1200 volume is idle capacity, and idle capacity is the most expensive thing on any sheet.

Servo drive and the closed hydraulic loop

The QST1500 pairs a servo system with an imported hydraulic system, an imported PLC touch screen, and closed-loop control of position, speed and torque. What that buys is repetition rather than a headline speed: the first block of a shift and the last block of a shift are formed by the same motion. On an open-loop drive, step loss creeps in as the oil warms, and the operator spends the shift compensating by hand.

The series figures for this drive family read as a cost statement. Electro-hydraulic integration is published at about 20 percent more output, full PLC control at about 15 percent less labour cost, real-time fault alarms at about 30 percent less troubleshooting time, and suspension vibration at about 10 percent less noise. A panel that names the failed station turns a stopped line into a two-hour repair instead of a lost shift, and that is a line item you cannot add later.

How to compare two QST1500 offers

Set the two sheets side by side and clear these five lines before you look at the totals.

• Machine weight in tonnes and vibration force in kN on the same page. 20 t and 220 kN are the QST1500 reference, and a sheet holding one of the two is incomplete.
• Tray size and thickness, 1,350 x 1,150 x 30 mm, plus the number of trays included in the offer. A line short of boards runs under capacity from the first week.
• Installed capacity at 69.1 kW, checked against your supply and against the mixer you plan to run behind the machine.
• Mould sets and the products they cover, because a second product needs a second mould, not a second machine.
• What sits outside the press price: pallet feeder, stacker, curing transport, commissioning and operator training. A low offer usually moves one of these out of the total.

An offer that answers all five is comparable with the next one. An offer that answers two is a number, and a number cannot be installed.