Industrial Sawmilling Highlights: Comparison of Wood-Mizer’s EG800 Edger and MR200 Multirip

Sawmill owners frequently search for methods to increase timber production, focusing on speed and efficiency. Wood-Mizer provides a variety of sawmilling machines designed to help expand your sawmill operations and boost your business's productivity. The first step to unlocking the potential of your sawmilling enterprise might be as simple as acquiring an edger or a multirip saw. But which is necessary for your operation? This article compares Wood-Mizer's industrial sawmilling solutions: the EG800 edger and the MR200 multirip. We will highlight their features and discuss how they can be effectively integrated into your business to optimize production.

The MR200 multirip (also gangsaw) has been designed for resawing cants with a maximum thickness of 200 mm (8”), a width of 540 mm, and a minimum length of 800 mm (the maximum length depends on how many modular tables are used). Its declared productivity is up to 10 cubic meters (4000 board feet) of ready boards per hour. 

It is a double-arbor machine with as many as 12 blades working on each shaft. It uses circular blades with a diameter of 200-350 mm. Blades with a diameter of 350 mm are recommended for thick cants, while blades with a diameter of 250 mm are recommended for thinner materials. Smaller blades are generally used to resaw thinner cants, thus generating less sawdust and yielding more timber.

A unique feature of the MR200 is the ability to adjust the arbors’ height. This is particularly useful while cutting thinner materials. “When you cut a 6-inch thick cant, you can adjust the shafts so that both shafts are loaded equally. In this case, the upper shaft will cut about 60% and the bottom 40% of the thickness, allowing the motors to work equally and distributing the wear-and-tear evenly on both shafts,” explains Adam Kubiak, Industrial Sales Manager. For manual adjustment, the operator uses three screws for the arbors – one is for changing the height, and the other two are for positioning the arbors. On the side of the machine is a scale to show the current height of the arbors. All covers to access the shafts and blades are protected with an electromagnetic lock that allows for opening only when the motors are physically stopped. 

The shafts are powered individually by two electric motors (one also drives the wood chipper). It helps cut prism with various thicknesses. “If you cut thin material, it is recommended to turn on only one shaft, with the other off, on which you don’t install any blades. This feature is convenient to those users who cut relatively thin materials, so they don’t have to use the upper shaft,” explains the specialist.  In that situation, the MR200 is used as a regular edger. Two amperemeters are built into the electric box to monitor power consumption.  

The power feed system (up to 15 m/min) and an automatic speed control mechanism make feeding cants easier. The feed speed decreases when the motors are overloaded. For precise feeding of the cant into the machine, there is a side fence, an assistant roller, and anti-kickback fingers at the entrance. A dedicated lever helps to return the prism that might get stuck in the shafts. As standard equipment, the MR200 is supplied with one infeed and one outfeed table (each 1,8 m long). The tables are modular, so the user can easily customize their length. 

The remote operator’s panel makes controlling the MR200 convenient. It can be moved around the machine quickly, making integration into a sawmilling line flexible. The operator panel includes the voltage indicator, protection lights, emergency button, motors on/off buttons, laser switch, reverse movement, power feed button, feed speed potentiometer, and gauge.  

The MR200 has an inbuilt chipper under the arbors that prevents wood pieces, debark, and sawdust from clogging the machine. Clogging is a common problem in a resawing process, which takes the operator away from work and makes him stop for cleaning. Apart from the chipper, there are two sawdust chutes (150 mm diameter outlets)  – one on top of the machine and the other at the bottom – to extract the sawdust from the machine. Wood-Mizer’s MES Dust Collection System is recommended for efficient removal of sawdust. “Remember to start the sawdust extractor first before turning on the MR200, or else you will clog the chutes easily,” points out Adam Kubiak.  

The EG800 single-head edger can also be used in a multirip mode, although its main application is board and cant edging. It has been designed to edge the material with a maximum thickness of 110 mm (4,5”), width of 640 mm (25”), and a minimum cutting length of 1,2m (4 ft). There are no maximum length limitations, as the modular feed tables can be added to the configuration to meet specific needs.  The EG800 can be easily integrated with the Wood-Mizer production line (SLP) or an existing customer’s line.  

The shaft inside the machine, with four standard circular blades of 375 – 400 mm diameter, assisted by four heavy-duty hold-down rollers, effectively resaws the material. A 30-kW or 55-kW electric motor drives the shaft and feed rollers. To inspect the blade compartment, the operator must release the locking levers and open the top cover; however, replacing the blades with shims and bushings is accessible through a smaller side outlet. “Adjusting the cutting width is easy with a spacer set with different thicknesses to fit the desired widths. All shims and bushings have an ID number engraved for easy reordering,” advises Adam Kubiak. 

The control panel is separated from the machine for better integration with the sawmilling line. The EG800 comes with Setworks for automatically adjusting the cutting width (one blade is moveable). On the operator panel, there is also an amperemeter indicating the load, the laser switch, reverse movement of the blade in case the wood gets stuck inside, a setwork/manual mode switch, feed speed potentiometer, emergency stop, and a laser movement switch. 

A belt conveyor underneath the machine efficiently removes sawdust. If necessary, the EG800 can be installed on an elevated stand and integrated into the existing production line with a different sawdust removal system. 

The main difference between an edger and a multirip is that edgers trim off the rough side from material such as sawmilled slabs and make evenly-edged boards with precise widths. On the other hand, a multirip is fed with a prism and rips it into precisely dimensioned boards. Generally, a multirip can process thicker material than an edger and is mainly used to produce cants rather than boards. 

“Edgers and multirips are perfect tools for expanding an existing sawmill installation. If a sawmill owner wants to raise the productivity of his business, he can add either a multirip or an edger to produce more timber quickly. How is it possible? Once the sawmill cuts only a thick prism, the edger/multirip can resaw the material to a desired dimension, making boards or cants. Splitting the production process into sawmilling and ripping on separate machines will increase efficiency and distribute the machines’ wear and tear equally,” says the specialist.  

Both machines, the EG800 and the MR200, allow for gradual sawmill expansion as they are easily adaptable to most Wood-Mizer sawmills, including the LT40 and LT70 and industrial machines. Sawmillers usually buy a sawmill as their first machine and add more components to their configuration with time. In addition, the EG800 and the MR200 feature replaceable circular saws with shims and bushings to adjust the width, so matching the desired dimensions and production volume to the current business situation is not an issue. 

Since the MR200 multirip is a dual-arbor machine, the shafts must be adjusted precisely to achieve the best performance. The MR200 can accommodate as many as 24 blades (12 per shaft) to effectively rip thick prism into boards. The EG800 edger is a single-shaft machine with four standard circular blades. Therefore, it is recommended for sawmill companies that mainly process one kind of wood, e.g., hardwoods. 

Compared to the horizontal resaws (Wood-Mizer’s multi-head HR500, HR700), which are usually limited to 6 heads, the MR200 double-arbor multirip is a compact machine with the possibility of adding up to 12 blades per shaft. It does not need much space to install, and it can work without the dedicated board-return system, for example, a merry-go-round return system. “All HR resaws need a blade change every 2 hours, and the operator must consider possible blade damage, while the MR200 works on the same set of circular saws for the entire work shift. Using the circular saws is more accessible than the sawmill blades, as they do not need frequent maintenance and do not cause a “wave effect” while cutting,” points out Adam Kubiak.   

To find out more about the sawmilling machines and accessories, please get in touch with the Wood-Mizer representatives by filling out the form - https://woodmizer.co.uk/contact

Read more about successful implementations of Wood-Mizer edgers and multirips in sawmilling businesses worldwide:

https://woodmizer.co.uk/learning-center/wood-mizer-tvs-hd-industrial-sawmilling-line-for-pallet-manufacturing 

https://woodmizer.co.uk/learning-center/how-edgers-and-multirips-add-value-to-a-sawmill

https://woodmizer.co.uk/learning-center/how-to-increase-timber-production-and-recovery

***