1. Introduction
Tangshan, often referred to as the “Bone China Capital of China,” plays a leading role in the global ceramic industry. With over a century of craftsmanship and innovation, the region is home to a dense network of bone china factories, each offering various production capabilities. One critical process in bone china production is decal firing — the step that gives each piece its final decorative look.
While factors like glaze quality and decal design matter, the type of kiln used for decal firing is equally crucial. In Tangshan’s bone china factories, two primary types of kilns dominate decal firing operations: the Roller Kiln and the Shuttle Kiln. These kiln types have a significant impact on the quality, consistency, and efficiency of the final products.
Understanding the differences between these kilns, their strengths and weaknesses, and when to use each can help buyers, designers, and sourcing managers choose the right factory for their specific needs. In this article, we’ll dive deep into how each kiln type works, the advantages and disadvantages, and how your choice can impact the final quality of your bone china products.
2. Overview of Kiln Types Used in Tangshan
In Tangshan’s advanced ceramic industry, you will primarily encounter two kiln types for decal firing: roller kiln vs shuttle kiln. Unlike bisque or glaze firing, which may utilize tunnel or saggar kilns, the decal firing process—requiring precision at relatively lower temperatures (around 780–850°C)—demands a kiln that ensures consistent and controlled heat distribution.
Roller kilns, also known as tunnel kilns, are continuous kilns. They operate like a conveyor belt, where bone china items move steadily through the heating zones on rollers. They are widely favored in modern production lines for their efficiency, automation, and consistency.
On the other hand, shuttle kilns are batch kilns. Products are loaded into a chamber that is heated all at once, then cooled after firing. They are often found in smaller workshops or older facilities. These kilns are flexible and cost-effective for small-scale operations but are prone to issues like temperature inconsistencies within the chamber.
Though both kilns are actively used in Tangshan, each suits different production needs. A smart sourcing strategy involves not only checking certifications and experience but also knowing what type of kiln your potential factory uses for decal firing.
3. Roller Kilns: Features and Advantages
Roller kilns are considered the gold standard for high-volume, high-precision decal firing. The defining feature of this kiln type is its continuous, conveyor-based operation, which ensures uniform heating as items pass through controlled temperature zones. This movement allows bone china pieces to be fired consistently with minimal temperature fluctuations.
One of the biggest advantages of roller kilns is their superior temperature uniformity. In decal firing, even small deviations in temperature can result in noticeable color variations, especially for reds, pinks, and metallic tones. Roller kilns maintain a stable environment, reducing the risk of color inconsistency and defects.
Additionally, roller kilns offer faster firing cycles. A typical decal firing cycle in a roller kiln can be completed in as little as 2 to 4 hours, compared to 8-10 hours in a shuttle kiln. This efficiency makes them ideal for mass production and time-sensitive orders.
Factories using roller kilns also benefit from higher yields and lower rejection rates, as the automation reduces human error and handling damage. For brands requiring strict quality standards, consistent color, and reliable delivery times, choosing a bone china factory equipped with roller kilns is the best option.
Advantages of Roller Kilns
One of the biggest benefits of roller kilns is temperature consistency. Every item passes through identical temperature zones, ensuring that decal colors remain uniform across batches. This is crucial for high-end tableware clients, where even slight color variations can result in product rejection. Additionally, roller kilns support high-throughput production, making them ideal for factories handling large-volume orders. Their energy efficiency is another plus, as heat loss is minimized compared to batch-fired systems.
For brands with strict quality standards — such as boutique hotel chains, luxury coffeeware brands, or export-focused wholesalers — roller kilns provide the color precision and repeatability needed to maintain brand integrity.
Disadvantages of Roller Kilns
However, roller kilns are not without challenges. One major limitation arises from the varying firing temperatures required for different decal types. Color decals, gold decals, and luster finishes (like electroplated gold) each require distinct firing temperatures. When multiple decal types need to be processed together, switching temperatures becomes difficult, leading to empty runs and significant energy waste.
This inefficiency means that roller kilns are best suited for large, consistent orders with unified decal requirements. Small or mixed-batch orders are more difficult to manage and less cost-effective.
As a result, operating roller kilns demands higher upfront investment, larger minimum order quantities, and advanced scheduling capabilities.
Because of this, the use of roller kilns is also an indicator of a factory’s scale and capability. Factories with roller kilns are often larger, with dedicated production planning and investment in automation, making them suitable partners for long-term sourcing relationships.
4. Shuttle Kilns: Features and Drawbacks
Shuttle kilns offer a more traditional, batch-based approach to decal firing. In this system, bone china pieces are loaded into a kiln chamber and fired all at once. While this method allows for flexible loading and is well-suited for custom or small-batch production, it has several important drawbacks when compared to roller kilns.
The most significant issue with shuttle kilns is temperature inconsistency. Because of the chamber’s size and static heating, it’s difficult to maintain uniform heat from top to bottom or across all corners. As a result, bone china items placed on different shelves may experience different firing temperatures, leading to inconsistent decal color or even under- or over-fired pieces.
This is particularly problematic for decals using temperature-sensitive pigments. A small change in heat can shift the final appearance of the artwork, especially for intricate, multi-colored designs. Inconsistent colors can lead to higher rejection rates, increased quality complaints, and costly rework.
However, shuttle kilns are not without advantages. They are cost-effective for small production runs and offer greater flexibility in firing odd-shaped or oversized items. For factories handling samples, prototypes, or limited editions, shuttle kilns provide the necessary adaptability. And not all designs are color-sensitive; many of the designs are acceptable in the shuttle kiln condition.
Buyers seeking economical or trial production may accept the risks associated with shuttle kilns, but for consistent quality, roller kilns remain the superior choice.
5. Decal Sensitivity to Temperature
Decals, especially those with rich colors, metallics, or gradients, are incredibly sensitive to firing temperature. A variation of even 5–10°C during firing can change the tone or intensity of the final color. For example, reds may appear too dark, gold lusters may lose shine, or delicate blues may turn pale or uneven.
This sensitivity makes temperature control during decal firing absolutely critical. Inconsistent heat can result in uneven decoration, ghosting effects, or even color bleeding — all of which reduce the product’s value and appeal.
Roller kilns are specifically engineered to minimize these risks. Their design ensures each item passes through a stable heat zone with minimal temperature variation, delivering consistent results across every piece. In contrast, shuttle kilns—due to uneven top-bottom heating—often struggle to deliver this level of control.
This is why many premium bone china brands insist on roller kiln decal firing, especially for large orders and complex designs. By understanding this technical nuance, buyers and sourcing professionals can make better decisions when choosing suppliers and factories.
6. Summary Table: Roller kiln vs Shuttle kiln
| Feature | Roller Kiln | Shuttle Kiln |
| Firing Type | Continuous, automated | Batch, manual |
| Temperature Uniformity | High -consistent across all items | Moderate – varies by position |
| Color Consistency | Excellent – ideal for sensitive decals | Inconsistent – risky for bold colors |
| Production Volume | Large-scale, mass production | Small batches, custom runs |
| Turnaround Time | Fast (2–4 hours per cycle) | Slow (8-10 hours per cycle) |
| Flexibility | Lower – optimized for standard sizes | standard sizes High – can accommodate varied items |
| Ideal For | Brands with a quality focus & large orders | Brands with a quality focus & large orders |
7. Choosing the Right Factory
When sourcing bone china products, especially those with complex or color-sensitive decals, it’s vital to understand the factory’s kiln setup. Ask whether they use roller kilns, shuttle kilns, or both, and how they decide which kiln to use for which order.
A reliable bone china manufacturer should be able to match the kiln type to your order’s requirements. For example, they might use shuttle kilns for prototype runs and roller kilns for mass production. Some experienced suppliers even coordinate with external facilities to access the right kiln for the job.
Choosing a factory with modern equipment, quality awareness, and flexible production planning will help ensure your bone china products not only look beautiful but also arrive on time, every time.