QT6-15 Automatic Block Making Machine

What Is a QT6-15 Automatic Block Making Machine?

The QT6-15 is a fully automatic hydraulic brick machine manufactured by Wojin Machinery for cement block manufacturing at medium to large scale. It uses a combination of high-pressure hydraulics and multi-directional vibration to compact cement-based materials into dense, uniform building blocks. The “6” in its model number indicates that it forms 6 concrete hollow blocks (400×200×200mm) per molding cycle, while the “15” refers to the 15-second forming cycle time.

The QT6-15 complete production line includes mixer, conveyor, block machine, and stacker

Overview and Working Principle

The QT6-15 operates on a straightforward but highly efficient principle: raw materials (cement, sand, fly ash, aggregate) are mixed in a forced-action mixer, conveyed to the machine hopper, fed into the mold cavity, and then compacted under simultaneous hydraulic pressure (21 MPa) and high-frequency vibration (50-70 Hz). The hydraulic press pushes down on the material from above while the vibration table shakes from below — eliminating air pockets and ensuring maximum density.

Once the forming cycle completes (15-20 seconds), the hydraulic press releases, and the finished blocks are pushed onto a wooden or plastic pallet. The pallet then moves via conveyor to the stacking area for curing. The entire process is controlled by a Siemens PLC control system with a touchscreen HMI, requiring only 1-2 operators per shift.

Raw Material Requirements

The QT6-15 is designed to work with a wide range of locally available materials, giving operators flexibility in sourcing and cost optimization. Here are the standard raw materials used:

• Cement — OPC 32.5 or 42.5 grade, typically 8-12% of the mix. Acts as the primary binder.
• Sand — River sand, manufactured sand, or stone dust (0-5mm). Makes up 25-35% of the mix.
• Fly ash — Can replace 20-50% of cement, reducing cost significantly. Produces fly ash bricks with excellent strength and smooth finish. See our fly ash brick setup guide for details.
• Crushed stone / Gravel — 5-10mm aggregate for solid blocks and heavy-duty applications.
• Slag — Industrial by-product that can replace sand, reducing material cost and environmental impact.
• Water — Clean water, typically 4-6% of the dry mix weight.

A typical mix ratio for standard concrete hollow blocks is: 10% cement, 30% sand, 50% fly ash or slag, 10% crushed stone. Adjust the ratio based on local material availability and desired block strength.

Key Features and Advantages of the QT6-15 Machine

The QT6-15 stands out in the block machine market because it balances high production capacity with affordability. Here’s a detailed look at its core technologies:

Hydraulic Pressure and Vibration Technology

The QT6-15 uses a dual-action compaction system — hydraulic pressure from above and vibration from below. The hydraulic system operates at 21 MPa (approximately 210 bar), which is significantly higher than the 12-16 MPa found in economy machines. This extra pressure produces blocks with compressive strengths of 15-25 MPa — well above the 7.5 MPa minimum required for load-bearing walls.

The vibration system uses a four-axis synchronized vibration motor arrangement. Vibration frequency is adjustable from 50 to 70 Hz, allowing operators to optimize for different material mixes. For coarse aggregate-heavy mixes, higher frequency ensures better flow; for fine fly ash mixes, lower frequency prevents segregation.

The hydraulic press and PLC control panel — the heart of the QT6-15

PLC Control and Automation System

The QT6-15 is equipped with a Siemens PLC control system featuring a 10-inch color touchscreen HMI. This system provides:

• One-button startup — the entire production line starts with a single touch
• Recipe storage — save up to 30 different mix and molding parameters for instant recall
• Fault diagnosis — real-time alarms and error logs for quick troubleshooting
• Production data tracking — records output, cycle times, and downtime for each shift
• Remote monitoring — optional remote access via internet for off-site management

The PLC system means even new operators can produce consistent, high-quality blocks after just 2-3 days of training. No specialized technical knowledge is required.

High Efficiency and Production Speed

With a 15-20 second forming cycle and 6 blocks per cycle, the QT6-15 achieves a production capacity of 8,000-12,000 concrete hollow blocks per 8-hour shift. That’s approximately 1,000-1,500 blocks per hour. In a 3-shift operation (24 hours), the machine can produce over 30,000 blocks per day.

Compared to manual block machines that produce 2,000-4,000 blocks per shift, the QT6-15 delivers 3-5x higher output — with fewer workers and more consistent quality. This makes it ideal for supplying blocks to large construction projects, government housing schemes, and commercial block-selling businesses.

Production Capacity and Output Analysis

The production capacity of the QT6-15 varies depending on the product type, material mix, and operator proficiency. Here’s a detailed breakdown:

Hollow Block Production Capacity

For standard concrete hollow blocks (400×200×200mm), the QT6-15 produces:

• Per cycle: 6 blocks
• Per hour: 1,000-1,500 blocks
• Per 8-hour shift: 8,000-12,000 blocks
• Per 24-hour day (3 shifts): 24,000-36,000 blocks
• Per month (25 working days): 200,000-300,000 blocks

At an average selling price of $0.50-$0.80 per hollow block in most African markets, the QT6-15 can generate $4,000-$9,600 in daily revenue (single shift). For more on block business profitability, see our block machine business startup guide.

Solid Brick and Paver Output

When producing solid blocks or paving blocks, output is slightly lower due to the larger material volume per block:

Main System Components and Equipment Setup

The QT6-15 is more than just a block machine — it’s the centerpiece of a complete cement block manufacturing line. Here are the key components that make up the full production system:

Concrete Mixer and Batching Plant

The QT6-15 pairs with a forced-action pan mixer (500-750kg capacity) or a twin-shaft mixer for larger operations. The mixer ensures uniform distribution of cement, aggregate, and water — critical for consistent block quality.

For automated batching, an optional batching plant can be added. It uses load cells to weigh each material precisely according to your recipe, eliminating human error and reducing material waste by 5-8%.

Conveyor Belt and Feeder System

A belt conveyor (6-8 meters) transports the mixed material from the mixer to the block machine hopper. The conveyor runs continuously during production, ensuring the hopper never empties and the machine operates at maximum efficiency.

An optional automated feeder with material level sensors can start and stop the mixer based on hopper fill level — further reducing labor requirements.

Automatic Stacker and Palletizer

The QT6-15 can be equipped with an automatic stacker (finger-type or vacuum-type) that picks up finished blocks on pallets and stacks them in the curing area. This eliminates the need for manual pallet handling — reducing labor from 4-5 workers to just 1-2 operators per shift.

The stacker can stack up to 6 pallets high, maximizing your curing area utilization. After 24-48 hours of curing, the blocks are ready for delivery and the empty pallets are automatically returned to the machine.

Types of Finished Products and Mould Options

One of the QT6-15’s greatest advantages is its versatility. By simply changing the mold, you can produce a wide range of concrete products from a single machine:

Hollow, Solid, and Interlocking Blocks

• Concrete hollow blocks — The most common product. Standard size 400×200×200mm with 2-3 voids for reduced weight and better insulation.
• Solid blocks — Dense, heavy blocks for load-bearing walls and foundations. Same exterior dimensions but no voids.
• Interlocking bricks — Featuring a tongue-and-groove profile that locks together without mortar. Popular for walls, fences, and retaining structures.
• Paving blocks — Colorful interlocking pavers for driveways, walkways, and public spaces. Learn about paving block production.
• Curbstone moulds — Road edge curbs, drainage channels, and traffic barriers for infrastructure projects.
• Fly ash bricks — Smooth, uniform bricks from power plant waste. See our fly ash brick guide.
• Grass pavers — Grid-style blocks that allow grass to grow through, used for eco-friendly parking and landscaping.

Customizable Moulds and Quick Change System

All molds for the QT6-15 are made from carburized heat-treated steel with a surface hardness of HRC 58-62, ensuring a service life of 100,000+ cycles. The mold change system uses a quick-lock mechanism — a single operator can switch between product types in under 30 minutes.

We also offer custom mold design services. If you need blocks in a non-standard size or shape (for example, a unique interlocking profile or a specific market requirement), our engineering team can design and manufacture a custom mold. Learn more in our mold selection guide.

Block samples — hollow blocks, solid blocks, pavers, and interlocking bricks from the QT6-15

Complete QT6-15 Production Line Configuration

Choosing the right configuration depends on your budget, available space, and target output. Here are the two main options:

Fully Automatic vs. Semi-Automatic Setup

Essential Auxiliary Equipment Requirements

Beyond the block machine itself, a complete production line requires:

• Pan mixer or twin-shaft mixer — $1,500-$8,000 depending on capacity
• Belt conveyor (6-8m) — $1,000-$3,000
• Pallets (200+ pieces) — $400-$1,500 depending on material (wood or plastic)
• Curing area — covered space of 100-300m² (no equipment cost)
• Forklift or hand truck — for moving pallets to curing and storage areas
• Optional: Batching plant — $3,000-$8,000 for automated material weighing
• Optional: Automatic stacker — $5,000-$12,000

Applications and Industry Scenarios

The QT6-15 serves diverse construction sectors. Here are the most common application scenarios:

Commercial Building Construction

For commercial building projects — offices, shopping centers, schools, and hospitals — the QT6-15 produces concrete hollow blocks and solid blocks that meet structural engineering requirements. Blocks produced at 21 MPa hydraulic pressure easily achieve 15-25 MPa compressive strength, suitable for load-bearing walls up to 3 stories.

Many contractors in Africa and Southeast Asia choose the QT6-15 to produce blocks on-site or near construction sites, eliminating transport costs and ensuring supply continuity. The machine’s production capacity of 12,000 blocks per shift can supply a mid-sized construction project single-handedly.

Paving and Infrastructure Projects

For government road projects, public plaza paving, and residential estate development, the QT6-15 produces paving blocks and interlocking bricks that withstand heavy traffic and weather. The machine can produce colored pavers by adding pigment to the mix, creating decorative patterns for urban landscaping.

Curbstone moulds are also available for road edge curbs and drainage channels — essential components of any road infrastructure project. By switching between paver, curbstone, and hollow block molds, a single QT6-15 can supply all the concrete products needed for a complete housing estate or road project.

Buyer’s Guide: How to Select and Purchase

Investing in a QT6-15 is a significant decision. Here’s what to evaluate before purchasing:

Evaluating Equipment Quality and Mold Durability

Not all QT6-15 machines are equal. When comparing suppliers, check these quality indicators:

• Steel grade: The frame should use Q345 or higher structural steel — not mild steel.
• Mold material: Look for carburized steel with HRC 58-62 surface hardness. Ask about mold lifespan (should be 100,000+ cycles).
• Hydraulic components: Top brands include Yuken (Taiwan), Bosch Rexroth (Germany), or Haoxin (China). Avoid unbranded hydraulic parts.
• PLC brand: Siemens or Mitsubishi PLCs are the industry standard. Avoid generic or unlabeled controllers.
• Vibration motors: Should be from reputable brands with proper sealing against dust.
• Weld quality: Inspect welds for uniformity and penetration. Poor welding leads to frame cracks under heavy vibration.

At Wojin Machinery, all our QT6-15 machines use Q345 steel frames, Yuken hydraulic systems, Siemens PLCs, and carburized molds. We provide a 2-year warranty and lifetime technical support. For maintenance best practices, see our 10 maintenance tips guide.

Comparing Alternative Models (QT4-15, QT6-15, QT8-15, QT10-15)

The QT6-15 isn’t the only option. Here’s how it compares to other popular models in our range:

For a detailed side-by-side comparison of the three most popular models, see our QT4-15 vs QT6-15 vs QT8-15 guide.

Pricing and Investment ROI Analysis

Here’s a typical ROI scenario for a QT6-15 operation in Africa: