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  • Chipping

Chipping systems

The heart of the woodroom

ANDRITZ has complete solutions for producing high chip quality with minimal wood loss.

The chipper:  heart of the woodroom

The chipper is the most important piece of equipment in the woodroom or woodyard because it has the potential to either produce high-quality chips or to destroy expensive raw materials.

Complete systems or specific equipment – ANDRITZ has the solution

ANDRITZ offers complete solutions for chipping that can be custom-configured to fit the layout and requirements of a specific wood processing application.  The scope of supply can vary from complete plants to individual equipment delivery.  ANDRITZ is very experienced in project management, ensuring deliveries that are on-time and on-budget, and produce excellent economic results for its customers.

The best chip quality at highest capacities

ANDRITZ offers a range of chipping systems that can meet the specific requirements and layout of a wood processing operation. There is a huge variation in incoming logs which has an effect on the chipping process. ANDRITZ has supplied over 1,100 chippers around the world and has built a depth of expertise.

As the leader in chipping technology today, ANDRITZ has delivered chipping systems that produce the highest chip quality at the largest throughput (world record is 500 m3 sub/every effective hour for a 20-hour period).  High capacities are achieved by uniform, constant, and simultaneous chipping of several logs at the same time across the whole width of the bed knife.

By optimizing the cutting geometry, the cutting speed, and other parameters affecting the chipping process, ANDRITZ chippers are designed to produce very high quality chips at high capacity, even from small diameter wood.

The basic prerequisite for producing very high and uniform chip quality is that each log must be correctly oriented in relation to the chipper disc during chipping. Once the first knife hits the log, the log must not rotate during the chipping sequence and the log flow must be stable.

Chipping systems available from ANDRITZ

  • HQ-Chipper
  • HHQ-Chipper
  • TwinChipper

ANDRITZ first developed the gravity-fed HQ-Chipper by tilting the shaft downwards and by optimizing its unique chipping geometry. This proved to be a major success.

By tilting the shaft further, ANDRITZ created the horizontally-fed HHQ-Chipper, which produces chip quality far superior to anything seen before. This became another major success. Looking at chipper orders over the past years, the majority (over 99%) have been horizontally-fed HHQ-Chippers.



This gravity-fed chipper is designed to produce high-quality chips at high capacity.  Practically speaking, it has been replaced by the horizontally-fed model except in replacement situations or at installations where the layout is very restricted.  The first HQ-Chipper was delivered to a mill in Finland in 1989, and the equipment performance and reliability has been improved over the years.

HHQ Chipper


The horizontally-fed HHQ-Chipper produces the highest quality chips at all capacity levels – even with large variations in wood supply.

Since its introduction in 2001 (to Metsä-Botnia’s Joutseno Mill in Finland) more than 110 HHQ-Chippers have been delivered around the world.  The biggest chipper in the world – the EXL-18I type with 18 knives – was delivered to Veracel Celulose in Brazil in 2009.

The TurnKnife chipper knife system in the HHQ-Chipper is known around the world for its durability and repetitive accuracy.  It is designed to achieve consistent chipping results, year after year, in even the most difficult working conditions.

The ChipperEKG effectively monitors chipper operations and diagnoses performance or maintenance issues. 

Twin chipper

Horizontally-fed TwinChipper

The TwinChipper is ideal for longwood chipping, which requires horizontal infeed to the chipper.  Longwood is fed to the TwinChipper by a conveyor. The horizontal spout is at the correct angle to the chipper disc to ensure optimum chipping.

The horizontal infeed, coupled with integrated breakage processing, result in improved chip quality and increased capacity.  Small pieces of wood sometimes break off the main stem during processing and can interrupt both throughput of the chipper and the chip quality.  This breakage is separated from the main feed line, collected in a separate conveyor, and fed to the chipper via a secondary drop feed spout located above the main chipper spout.  This arrangement not only extracts the highest possible chip quality and yield from breakage, but also ensures an undisturbed flow of logs to the main spout which increases the capacity of the chipper and improves the chip quality.

The large disc diameter infeed accommodates crooked wood, while the lower cutting speed minimizes the generation of fines and pins. Gentle side discharge of chips reduces fiber damage caused by the blowing wings of the chipper disc.

Benefits of the ANDRITZ TwinChipper

  • Reduced chip damage
  • Horizontal feeding of tree-length wood
  • Minimal oversize and overthick chips
  • Highest possible chip quality and yield from breakage
  • Low pins and fines generation

Gravity-fed HQ-Chipper

Proven chipping technology combined with latest research yields an excellent HQ-Chipper for small diameter pulpwood.

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Horizontally-fed HHQ-Chipper

The horizontal infeed to the HHQ-Chipper aligns and holds the logs in the same position relative to the chipper disc to ensure high-quality wood chips.

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  • HQ-Chipper PDF : 354 KB
  • HHQ-Chipper PDF : 316 KB