(L-R) Planer tool, circular saw blades and profile and counter-profile tool.

By GIORGIO BATTISTELI

The door manufacturing sector in India is experiencing significant transformation, with the industry increasingly embracing automation. Typical factories are designed to produce up to 200 doors in an 8-hour shift.

To achieve this sustainably while maintaining quality standards and ensuring satisfactory profit margins, it is essential to establish effective synergy between machinery and tools.

It is important to choose the correct circular saw blades for door manufacturing operations, with different blade types serving specific purposes in the production process. An important factor is tooth geometry. The most popular geometries are alternate bevel (ATB) and trapezoidal flat (FZTR or TCG).

ATB is the preferred geometry for ripping and cross cutting. Use a blade with rakers in case you need to rip wet wood. FZTR/ TCG is the preferred geometry for laminated panels.

Fire doors will have one or more layers of calcium silicate or similar material. Due to its abrasive nature, calcium silicate causes higher wear and tear of the tips.

It is recommended to use either PVDF coated blades or PCD blades for fewer interruptions during production.

Precision shaping

Milling is an important operation during the production of doors. Common operations include four-side sizing (also known as formatting); rebate door groove cutting and profile shaping; fire door precision cutting for intumescent strip channels; lock and hinge mortising operations; and door closer and drop seal grooving.

There are multiple options for milling tools. Some of the most popular are:

•        Replaceable TC knives. These can be either straight or in a “compression” form for excellent finish on top and bottom.

•        Solid carbide tools (1, 2 or 3 spirals) are also very common. These can have chip breakers which are especially useful for deep cuts like lock body mortising.

•        PCD tools are chosen for the exceptional life they provide. It would also be helpful to choose the right tool holder.

•        Conventional chucks which have a chuck, collet and lock nut are popular due to their low cost and flexibility. However, they can have a higher run out (10-20 µm) and hence feed speed and/or quality could be compromised. If you must choose these chucks, invest in high precision collets. Remember to replace collets at regular intervals.

•        Hydro chucks using oil for locking provide excellent stability (runout under 3 µm) and flexibility, but their upfront costs are much higher than standard chucks.

•        Shrink fit chucks provide high quality with runout under 3 µm and are cost-effective, but require special tools for operation, limiting flexibility.

Runout significantly affects dimensional accuracy when using small or long tools. Minimizing runout improves tool life, reduces spindle wear, and can extend tool life by up to 60% when limited to 3-5 µm.

Profile shaping

Four-side molders require specialised cutting tools that can simultaneously shape all four sides of door frames. These machines utilise cutterheads with indexable carbide inserts that provide consistent cutting performance and easy maintenance. The typical setup includes:

•        Horizontal spindles (top and bottom) with cutting circle diameters ranging from 112mm to 200mm and length of 230 mm. First horizontal spindle is used for creating a reference. Subsequent horizontal spindles could be used either for grooving (grooves for intumescent strip or profiles) or for giving the final finish.

•        Vertical spindles (left and right) typically have a cutting circle diameter between 100-200mm and a length of 100-140 mm. They are used for edge profiling or grooving for rubber beadings.

•        It is quite common for customers to use a saw blade to retrieve the beading patti from the door frame. This operation uses a tool that combines a planer and a saw blade.

The four-side molder operation requires precise coordination of multiple cutting heads, each powered by independent motors ranging from 5 HP to 10 HP. These machines can process door components with working widths from 25mm to 230mm and thicknesses from 8mm to 120mm.

Door frame tools (L-R) on Powerlock, multi-profile door tools for CNC, and PCD door frame tool.

Door frames

Tenoning machines utilise specialized cutting assemblies that include saw blades, dado heads, and purpose-built tenoning cutters. Modern CNC tenoning machines offer parametric programming capabilities, allowing for precise tenon cutting with minimal setup time. Their key features include:

•        Carbide cutter blocks for durability and precision

•        Adjustable cutting depths from 5mm to 45mm

•        Variable spindle speeds from 9,000-18,000 RPM

Double-end tenoning machines can process both ends of door components simultaneously, significantly increasing production efficiency. These machines typically feature continuous revolution cutters around the workpiece, ensuring consistent quality across all cutting angles.

The investment in quality cutting tools is fundamental to achieving the precision, efficiency, and quality standards demanded in today’s competitive door manufacturing market.

As the industry continues to evolve with new materials and manufacturing techniques, the importance of selecting the right tools for each specific application becomes increasingly critical for sustained success.

– The writer is owner of BUP Utensili S.r.l. a leading manufacturer of woodworking tools in Italy for 50 years. For more information, write to info@buputensili.it

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