Kerbstone and Paver Demand in Iraq: Moulds, Surfaces and Changeover Time
18 October 2026 · 6 min read
Quick answer
A kerb and paver contract is settled by the mould count, not by the machine count. Each product needs its own mould set in wear-resistant alloy steel, and each set change costs hours plus the first shots scrapped while the mould and mix settle. A QS1000 unidirectional presses pavers on a 1,100 x 850 mm moulding area, 32 pieces of 200 x 100 x 60 mm per cycle, at 31.5 MPa and a 20-25 s cycle.
Kerbstone and paver demand in Iraq is decided by the mould count before it is decided by the machine count. A kerb is a deep, narrow section. A paver is a flat one with a face that customers judge by eye, and the two do not come off the same tooling. Every product you add is a mould set, a changeover, and a run of first shots that go to waste while the mould and the mix settle.
What does a kerb stone demand from the press?
A kerb stone is a deep, narrow section. The load has to travel down a tall cavity and still reach density at the base, where the mix has the least room to move. Vibration shifts a mix sideways and lays it against a mould wall; it does not drive density to the bottom of a vertical pocket. A static press does. The ram closes, the load builds to 31.5 MPa, and the press holds that load while the air leaves the section and the corners fill.
Dwell time is the field most buyers leave out of the comparison. On the bidirectional frames the cycle is quoted at 18-22 s. On the unidirectional frames it is quoted at 20-25 s. The names describe the pressing direction: a bidirectional frame closes on the section from both ends, so a deep kerb reaches density in less time, while a unidirectional frame has to hold longer for the same result at the base. The cylinder bore sets the force behind that hold: 500 mm on the QS800 pair, 600 mm on the QS1000 pair and 720 mm on the QS1500 pair, all at 31.5 MPa.
Ask for the dwell in seconds on the product you intend to sell, not the cycle time on a hollow block. A press that cycles quickly on a hollow block and only touches a kerb will send out kerbs with soft bottoms and corners that chip in handling.
What is inside a mould set, and why a second product needs a second one
A mould is not a plate with holes in it. It is a set of five parts, and each one does a job a different product breaks. The frame carries the outline. The core forms the voids, the chamfers and the interlock profile. The base plate sets the bottom face and the height. The guiding assembly keeps the core and the frame aligned through the stroke. The positioning mechanism locates the set in the machine, so the same position repeats every cycle.
The set is cut from wear-resistant alloy steel, machined on CNC equipment and hardened in a controlled cycle. That sequence makes a chamfer repeatable and a kerb face square, and none of it is adjustable from the control panel. You cannot turn a paver mould into a square mould by changing a setting, and you cannot turn either into a kerb mould. A second product is a second mould, with its own cavity layout and its own piece count.
How many pieces come off one cycle?
Piece count follows the moulding area, not the tonnage. The QS1000 unidirectional carries a 1,100 x 850 mm moulding area on a 1,200 x 900 x 20 mm pallet, and takes 32 pavers of 200 x 100 x 60 mm, or 12 squares of 250 x 250 x 60 mm. The QS1500 unidirectional opens to 1,440 x 850 mm and takes 40 pavers of the same size, or 15 squares. The QS600 works an 850 x 700 mm area on a 900 x 700 x 20 mm pallet and takes 16. The QS800 unidirectional takes 24 on 1,100 x 680 mm.
Read the count as a pallet rate. A 32-piece mould on a 20-25 s cycle fills one pallet per cycle, so the curing yard and the handling equipment are sized on pallets, not pieces. The same area gives 32 pavers or 12 squares, because the mould decides the layout and the press only supplies the force.
What does a changeover cost in hours and rejects?
A changeover is paid twice: once in hours off the line and once in the first shots that go to the waste pile. The mechanical half is visible: the old set out, the new one in, the positioning checked, the height and the pressure re-set, the first pallet run and inspected. The second half is slower. A fresh mould runs cool, the mix in the hopper was built for the previous product, and the first shots come out with soft corners, a dull face or a height that drifts before it settles.
Those first shots are predictable scrap, and they belong in the plan rather than in the operator's surprise. The rule that follows is one product per shift. Two products in one day means two changeovers, two settle-in runs and two scrap allowances. Hold stock of the slower mover instead, and leave the mould on the machine for the whole shift.
Where the surface comes from: face mix and texturing
On a paver, the surface is the product. Two buyers can order the same 200 x 100 x 60 mm base and reject or accept on the face, so the face is designed, not left to the mix. That means a face mix: a second layer over the base mix, finer and richer in pigment, compacted in the same stroke. The base mix carries the strength; the face mix carries the colour and texture the buyer sees.
A face mix needs its own feed: a second hopper and a separate mixing step, or a colour mixer that charges the mould before the base mix arrives. The texturing step comes after demoulding and before curing, a brush, a roller or a stamp that opens the surface while the concrete is still green. Both steps belong on the line drawing, because the cycle has to leave room for them.
What do you send the supplier with a mould order?
A mould order moves faster when four documents travel with it. The tolerance band matters as much as the shape, because it decides how the set is fitted and how the first shots are judged. The pallet size and the machine model together decide the fixing pattern and the moulding area the set has to fill.
- Product drawing: the shape in plan, the section, the chamfer and the face finish.
- Block drawing with tolerances: the band you will accept on length, width, height and square.
- Pallet size: the plate the set is fixed to, including its thickness.
- Machine model: it fixes the moulding area, the stroke and the locating pattern.
Count the moulds, not the catalogue
A long product list is a catalogue, and every line on it is a mould, a changeover and a settle-in run. The plant that starts with two moulds, runs each for a full shift and adds the third when the first two are selling keeps its hours on the machine. The plant that orders a full catalogue of products and moulds at once spends its first year learning which ones it should have bought.
The buying question is not how many products the machine can make. It is how many moulds the first year of orders will pay for.
Frequently asked questions
Why do kerb stones need a static press rather than a vibrating table?
A kerb is a deep, narrow section, and vibration moves a mix sideways instead of driving density to the base of a tall cavity. A static press builds 31.5 MPa and holds it for a dwell, 18-22 s on the bidirectional frames and 20-25 s on the unidirectional ones. That hold closes the corners and the bottom of the section.
How many 200 x 100 x 60 mm pavers come off one mould?
The count follows the moulding area. The QS600 takes 16, the QS800 unidirectional 24 on 1,100 x 680 mm, the QS1000 unidirectional 32 on 1,100 x 850 mm, and the QS1500 unidirectional 40 on 1,440 x 850 mm. A 250 x 250 x 60 mm square returns 8, 12 or 15 pieces on the same three unidirectional machines.
Can one mould set run both a kerb and a paver?
No. A set is a frame, core, base plate, guiding assembly and positioning mechanism, cut and hardened for one product geometry. The core forms the profile and the base plate sets the height, so a paver mould cannot produce a kerb section at any pressure setting. Count the moulds you need first, then count the machines.
What happens to output during a mould changeover?
You lose the hours the line stands still and the first shots that go to waste while the new mould and the mix settle. The mechanical swap is the short part; the settle-in is the long one. Plan one product per shift and hold stock of the second product instead of changing over twice in a day.
What should a buyer send with a mould order?
Send four items: the product drawing with the section and the chamfer, the block drawing with the tolerance band you will accept, the pallet size, and the machine model. Those four fix the cavity layout, the fixing pattern and the moulding area. Without them the supplier quotes a shape, not a mould.
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