Reprinted with permission from MLS Machinery, Inc.
Moulders are specifically used for the solid wood or MDF (Medium Density Fibre board a more dense product than particle board) industry and as their name implies, are used for moulding. Mouldings are used in many different applications, to name a few, frames around a door or window, door stops to stop the door from going all the way in and out (doors normally open in one direction), one style of flooring that is very common is called tongue and groove where one side is protruding called the tongue and the other side has a groove, ornate trim work seen on older houses, wainscoting, picture frames, etc. These are very common machines, newer machines being quite expensive. Moulders can be made in various lengths for different applications from two heads for very simple work all the way up to 12 heads which are not very common.
There are basically two types of moulders: one is a push feed model and the other is a through feed model. A push feed moulder is where the operator takes a solid piece of wood, pushes it into the machine and eventually the feed mechanism and some of the cutters will grab this piece of wood; however, the wood will only continue going through the machine by the operator pushing the next piece behind the first, and so on. A through feed moulder is where the wood is placed on an in-feed table and the feeding mechanism takes the wood and feeds it through the machine on its own. Some people prefer through feed machines while others still prefer push feeds.
Through feed moulders have two different drive systems: one is called a chain feed where the feed roll mechanism actually runs on a sprocket and chain system similar to a bicycle chain. The other system is called Cardan Drive which is a more sophisticated system; however, if it breaks down, it is more expensive to fix. It is a more positive action which operates similar to the drive shaft and U-joints on a motor vehicle. This style of feeding mechanism is stronger than the chain system to avoid the piece getting stuck in the machine, as this can burn the wood while the cutters are still turning and the piece has stopped moving through the machine. Therefore, Cardan Drive has become very popular.
Moulders come in various widths the most common being four inches, six, seven and nine inches. Some applications will require 12" wide and some application 24" but these are not very common. As stated before, these machines can have a number of heads which will either have a similar or different shape of tool on each head. The sequence of heads is normally described as follows: bottom, top, fence side and near side. The fence side, also known as the far side, is the one furthest from the operator and is the side that the piece of wood is pushed against. The side head, sometimes referred to as the near side, is closest to the operator. In certain cases (becoming very rare) some people prefer a top head first then a side head; however, the most common today is the first head being a bottom head and the second would be the fence head (or far side). This is critical because the first head will receive the material which might be unequal in thickness; therefore, the first head being similar to the jointer (as discussed under Jointers) will clean the material from the bottom first to make it perfectly flat (or jointed). The second (fence) head would receive the material that again would not necessarily be equal in thickness, and would joint it from the side;
thereby making it perfectly flat, which would now create a piece of wood that is perfectly flat on one side and the bottom. This becomes imperative as we now have a perfect 90 degree piece of material that is sitting flat on the table and flat against the fence; therefore, all the other operations in line can now be indexed off this perfect 90 degree piece of wood.
In an example of a seven head machine which could be described as bottom, fence (furthest from the operator), near (closest to the operator), top, bottom, etc. When this is described to a user, the user would now know the location and sequence of each of the heads. For specific applications this becomes critical; for example in flooring, where a customer is going to mould a tongue and groove style floor, as described above. Two sides, that is one fence and one near side, should be directly opposing each other so that the tongue and groove match exactly when laid down on the floor.
Most through feed moulders have a long in-feed table also known as a jointing or straightening table. After the piece passes the second head the rest of the moulding heads would do the other operations to the piece from the side, the top, the bottom, etc., depending on the desired shape and operation of the individual cutters. In some cases, the machine might have a splitting saw (works like a small multiple rip saw) on the very last head, so when small picture frames are being made on for example a 9" wide machine, nine 3/4" frames could be made at one time, then using the splitting saw at the end, split them into nine separate picture frame mouldings after all the other operations are complete.
Everything hinges on the tooling, the tooling is very critical in moulding operations. To get the desired quality, many customers do their own tooling "in house" with tool grinders (do not confuse with wood waste grinders). Tool grinders cover grinding equipment so the company can produce their own cutters to fit the specific job. This is critical in order to get a constant finish, especially seeing the cutters (also known as knives) do not last very long as they are being fed thousands and thousands of lineal feet at a time producing the same part, the tooling constantly has to be re-sharpened to exact tolerances. Some people have now gone to diamond tooling, which is very expensive, but lasts for a long time especially for jobs running hundreds of thousands of feet.
Some moulders have a universal head on the back end, which is a head that can be turned to be used either as a top, bottom, left or right head. Moulders are now becoming more sophisticated and many of the head set up is being done by C.N.C. control because as with most moulders having numerous heads the set up time can be quite long because of the exactness required. Another generic name for moulders is stickers.
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