QST6-15 Block Making Machine: 34.4 kW on the Smallest Footprint
11 October 2026 · 6 min read
Quick answer
The QST6-15 is the smallest fully automatic frame in the range, and it works at 25 MPa hydraulic pressure with a machine weight of 12 t. That pressure handles standard bricks, Holland pavers and ordinary hollow blocks with sound faces and clean edges when the mix and the curing are right. Load-bearing blocks, interlocking pavers and kerbstones need 31.5 MPa, where a larger frame holds density with less cement in the mix.
QST6-15 block making machine is the smallest fully automatic model in our range. It weighs 12 t and measures 9,450 × 3,300 × 2,700 mm, so it fits a yard where a bigger line will not. Installed power is 34.4 kW, and a site supply of about 30 kW is enough to run it. This article covers the 25 MPa working limit, the products that still hold at that pressure, the output maths on a 980 × 680 × 20 mm pallet, the power rules for a generator, and the upgrade path to a larger frame later.
1. What yard does a 12 t machine at 34.4 kW fit?
The machine body is 9,450 × 3,300 × 2,700 mm, the smallest frame we build. Reserve clear space at both ends of that 9,450 mm length for the pallet feeder and the green block stack. The frame weighs 12 t, so the slab carries a point load under each leg, not a spread one. A level slab with isolation pads under the legs is enough at this weight. You do not need a piled foundation.
Two practical checks belong in the site plan. Keep the mixer close enough that the skip reaches the feed hopper without a second machine, and leave a clear lane for the forklift that carries green blocks to the curing area. Drainage under the slab matters more than slab thickness here. Standing water under the frame rusts the legs and softens the ground.
2. The 25 MPa boundary: which products hold and which need 31.5 MPa
Hydraulic pressure sets how hard the mix is pressed before it leaves the mould. This model works at 25 MPa with 68 kN of vibration force. Standard bricks, Holland pavers at 200 × 100 × 60 mm, and ordinary hollow blocks come off a 25 MPa machine with a sound face and clean edges, provided the mix and the curing are right.
Load-bearing blocks, interlocking pavers, and kerbstones need more pressing force. For those, a model at 31.5 MPa with a larger vibration force holds density with less cement in the mix. Pressing dense products on a 25 MPa frame usually means adding cement to reach the test strength, and that costs more per block than the step up in machine would have cost.
3. Output maths on a 980 × 680 × 20 mm pallet at 15 to 23 seconds a cycle
Start from the cycle. At 15 to 23 seconds, one line completes roughly 156 to 240 cycles in an ideal hour with no stoppages. Multiply that by the number of blocks in the mould, then take off a realistic availability allowance for pallet return, mix delivery, and normal pauses. The 980 × 680 × 20 mm pallet is the smallest we make. It keeps pallet cost and handling weight down, and it limits how many cavities one mould can carry.
Do this sum before you buy, not after. Write down the product you sell most, count how many units fit one mould, and work out cycles per hour against a realistic shift length. If the result sits below what your market buys from you today, this is the wrong frame size for you.
4. Power: about 30 kW of supply, 5 to 7 times starting current, and the generator to match
Installed power is 34.4 kW, and a site supply of about 30 kW runs the machine and its 3.0 kW stacking unit in normal production. The trap is starting current. An induction motor pulls 5 to 7 times its rated current while it accelerates, and a cycle of 15 to 23 seconds means the vibration motors start more than 140 times an hour. A generator sized on running kW only will stall on the first start.
Size the generator on starting current, and check both figures before you pay for it. Ask the supplier for the locked-rotor current of the main motor, then compare it with the short-time overload rating of the generator. We ask for your site voltage, your transformer size, and how you plan to feed the line before we quote the electrical package. Do not assume a standard supply suits the machine. Send us the data and we match it.
A soft starter or a star-delta start often solves the surge on a small site. A separate feed for the machine also keeps voltage steadier while a welder or a crusher runs on the same transformer. We review your single line diagram before shipment, and a short check there is cheaper than a stalled start on site.
5. Crew and site routine on a small line
A line like this does not need the crew a bigger machine needs. Our 8-15 line runs with 4 to 6 people per shift. On this frame the stacking machine does the heavy handling, so the packing station works with one person, and the rest of the shift goes to the mixer, the forklift, and quality checks.
Curing area is the part most customers underbuild. Block strength comes from hydration in the days after moulding, and that depends on temperature and moisture, not on the machine. Work out your daily output in blocks, then plan rack space for the full curing period. Pallet count and curing racks are usually the cheapest place to add capacity later.
6. Upgrade path: what to reserve now for a larger frame later
The 6-15 and the 8-15 share a layout family, but the numbers are close, not identical. The 8-15 frame is 9,800 × 3,600 × 2,800 mm, 14 t, at 44.9 kW, and it needs a supply of about 45 kW. The QST1200 is longer again at 11,500 × 4,550 × 2,800 mm and 57.6 kW installed. Moving up later means a longer slab, a bigger transformer, and more curing racks.
If you can only afford one of those three reservations now, make it the slab and the electrical feed. Concrete work is disruptive once the yard is busy, and a transformer upgrade takes weeks. Pour the longer slab today, run the cable tray to the far end, and size the incoming panel for the bigger machine. Then the swap is a crane day, not a shutdown.
Frequently asked questions
What products can the QST6-15 block making machine produce?
It presses standard bricks, Holland pavers, and ordinary hollow blocks at 25 MPa with 68 kN of vibration force. Those products hold shape and edge quality when the mix and the curing are controlled. Load-bearing blocks, interlocking pavers, and kerbstones are better made on a 31.5 MPa model with a larger vibration force, because they need more density at the same cement content.
How much power does the QST6-15 block machine need?
Installed power is 34.4 kW, and a site supply of about 30 kW runs the machine with its 3.0 kW stacking unit. The generator has to be sized on starting current, not running load, because an induction motor pulls 5 to 7 times its rated current at start. Send us your site voltage and transformer size and we size the electrical package with you.
How much output can I expect from a 980 × 680 × 20 mm pallet?
Output equals cycles per hour times blocks per mould, minus a realistic availability allowance. At 15 to 23 seconds a cycle, one line completes roughly 156 to 240 cycles in an ideal hour. Multiply that by the cavities in your mould and then discount for pallet return, mix delivery, and normal pauses. The pallet size limits how many cavities one mould can carry.
Does the QST6-15 need 25 MPa or 31.5 MPa for hollow blocks?
Ordinary hollow blocks run well at 25 MPa on this machine. If you sell load-bearing units, kerbstones, or interlocking pavers, plan for 31.5 MPa and a larger vibration force instead. Pressing dense products on a 25 MPa frame usually means adding cement to reach the test strength, and that costs more per block than stepping up to the bigger model would.
Which machine should I buy if my site power is limited?
A limited supply points to this model. It needs about 30 kW of site power, against roughly 45 kW for the 8-15 line and 57.6 kW installed on the QST1200. Check the starting current first, then the running load, and confirm the transformer can carry the surge. Tell us your supply and we will confirm the match before you order.
Can I upgrade to a larger machine later?
Yes, and it costs less if you prepare for it now. Pour the longer slab, run the cable tray to the far end, and size the incoming panel for the bigger frame from the start. Concrete work and a transformer upgrade are the two slow jobs. The 8-15 frame is 9,800 × 3,600 × 2,800 mm at 14 t, so the difference in footprint is real.
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