Definition and explanation of face milling in woodworking
Face milling is a woodworking technique in which a workpiece is milled to a desired thickness. Accurate angles and even surfaces are important for beautiful and high-quality wood products. Raw wood from the saw is not suitable for decorative purposes, which is why it is dried and processed. Face milling is an important step to achieve a smooth and even surface.
In this article you will learn everything about face milling, how it differs from other techniques, which materials can be machined with it and there are other possibilities with the milling machine.
Definition: What is face milling?
Face milling is the flattening of a wavy surface from a solid material. Face milling (or “planning” for short) is a secondary process that follows directly after sawing.
Professional woodworkers do not use milling machines for planning, but planing machines. These thickness planing machines usually have one, sometimes two, rotating planer shafts with one or more integrated knives. The piece of wood is first guided over the so-called “dresser” to plan the first side flat. It is then brought to the desired material thickness in the thickness planer.
The planer and thicknesser work very quickly. However, they can technically only perform this one function. In addition, the width of the workpiece to be machined is limited to the length of the planer shaft. A face milling machine does not have both disadvantages. It can process panels or solid wood parts of any size. Although the machining takes longer, a face milling machine is very versatile and can perform a whole range of functions. This includes, for example, formatting or setting an even row of holes. With a face milling device, end-grain wood can also be processed very well, which would tear out with the planing machine. This makes the face milling machine a good all-round tool for the small wood workshop.
Technical basics of face milling
A face milling machine consists of the following components:
- changing tool
- Working table with clamping devices
- XY guide with detents and immersion mechanism
Face milling machines are available for all budgets and applications. Hobby machines consist of a commercially available hand router with a milling device that can be dismantled. If necessary, this can be set up on the work table. After processing, it can be stowed away again to save space. Professional devices not only have a fixed structure, but also a CNC control if necessary.
Each face milling machine is equipped with a chuck for changing tools. This allows you to replace a blunt cutter with a fresh one in just a few simple steps. Since face milling puts a lot of strain on the tools, face milling cutters with indexable inserts are recommended. These can be quickly made operational again by loosening and turning the plates. Routers are designed to accommodate different types of cutters. Milling tools with a wide diameter are suitable for face milling. You plan a surface particularly efficiently.
The work table is the basis on which the milling device is built. The existing workbench is sufficient for the hobby workshop. It should be large enough to accommodate the face milling machine. With a stable, straight stand, the best results are guaranteed. A clamping device ensures that the workpiece does not slip during processing.
In addition to the router, the milling device including the XY guide and immersion mechanism is the heart of the system. The XY guide consists of two parallel rails that are mounted one above the other. The router is built into the immersion mechanism. This is connected to a slide with the XY guide. The router can be moved steplessly along the directions. The movement of an axis can be blocked by detents. This is useful, for example, for formatting a workpiece.
Simple face milling machines work with a guide that can be dismantled and a detachable hand router. Both components must match. Not every hand router is compatible with every type of face milling guide system. This is something to consider before you buy. The integrated collet is usually designed for tools with a diameter of 8, 10 or 12 mm.
An adjustable speed range on the router adapts the tool to the material to be processed. Excessively high speeds can lead to burns on soft wood, for example, and the tool can wear out quickly. Such undesirable effects are avoided with an adjustable rotation speed.
The use of interchangeable tools makes the router particularly versatile. Manufacturers today offer a huge selection of different machining tools. This allows a workpiece to be shaped in practically any way. Despite this versatility, the basic structure of a milling tool is always very similar. It consists of the following components:
- milling body
- Cutting, fixed or reversible knife
The shank is the basic shaft that is clamped into the machine on one side and that carries the cutter body on the other side. The cutting edges are attached to the milling body. Small tools do not have a milling body, but cutting edges milled into the shank. These tools are also called “end milling cutters” with a fixed cutting edge. They are mostly made of solid carbide. Both the end mills with an integrated cutting edge and other milling cutters with a fixed cutting edge can be resharpened several times.
Milling devices are comparably simple structures. They consist of two parallel double rails arranged one above the other at right angles. The pairs of rails can be moved relative to one another. The holder with immersion device for holding the router is attached to the upper rail. This can also be moved along the top rail.
For really good results, professional devices are the best choice. They consist of precision machined parts and many comfort features. An example of this is the SlabMatrix from Sautershop . These milling devices can also be dismantled. As long as they are not needed, they can be stowed away in the workshop to save space.
The work surface determines the size of the milling devices that can be accommodated and the work pieces that can be processed. It therefore consists of a plate that is as large, flat and stable as possible. Countertop finishes depend on your budget.
As a basic version, for example, a block board with two stable trestles is sufficient. Designed as a perforated plate, you can quickly and easily fix the workpiece on it with bolts. Professional work tables have height adjustment and matching accessories. These include screw-on clamps, clamps, stops and much more.
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Which face milling cutters are used in face milling?
In most cases, face mills with an 8mm shank and a diameter of around 30mm will do the job best. The milling cutters have two or three cutting edges. Recommended manufacturers are Titmann and ENT.
What materials are used in face milling
Face milling cutters are used to level uneven surfaces. In wood processing, this applies above all to solid wood of all kinds. Chipboard, laminated beams and plywood usually already have an even surface. In these cases, grinders are the better choice to even out slight unevenness.
Workpieces made of different materials can also be machined with face milling cutters. The combination of solid wood and acrylic or epoxy resin is an example for spectacular table tops and cupboard doors. The panels are prepared for finishing using the face milling machine.
Solid plastics such as panels made of recycled plastic can also be easily processed on face milling machines. It is only important that the materials have no metallic inclusions. This would damage the face milling cutters.
Fields of application of face milling machines
A face milling machine can be used for the following fields of application:
- Leveling a surface
- Formatting a workpiece
- Incorporation of hole patterns, pockets and recesses
- edge processing
The versatility of the face milling machine makes up for the disadvantage of its slow processing compared to the planer. This makes it a practical tool for workshops with limited space.
The face milling machine can be used very well to process end-grain surfaces, e.g. on cutting boards or tree discs. Table tops made from a wood-epoxy resin mix can also be milled flat and are therefore ideally prepared for grinding and polishing. If the milling device has flexible stops, it can also be used to format a workpiece or mill a cut-out (e.g. stove cut-out on a kitchen worktop). Professional devices also offer a detent to drill rows of holes with the router and the appropriate router for cupboard sides or for self-made hole grid tables.
Creating a flat surface
The primary task of face milling machines is to produce an even and smooth surface. Planks, beams, boards and blocks made of solid wood can be further processed into easily usable semi-finished products. In addition to fresh wood from the sawmill, old wood from roof trusses can also be used for new products by face milling.
This work is actually a task for planers and thicknessers. The face milling machine works more slowly and has a higher wear on the tool. But it is more versatile and can be used for other tasks. In addition, a face milling machine is only limited in the way it is processed by the length of the rails from the milling device. This means that much larger workpieces can be processed on this device than on a normal thickness planer.
Face milling of bumps and overhangs
Face milling is not only suitable for the preparation of workpieces. It also serves to optimize a product during the manufacturing process. Glued connections with the organic material wood often do not sit exactly together. Hardened glue contributes to the roughness of the surface. Face milling produces a flat surface again. A final sanding ensures the perfect finish.
Mill pockets, indentations and recesses in surfaces
The wide range of processing options is the greatest advantage of the face milling machine over the thickness planer or the planer. The face milling machine can work any pockets, indentations and recesses into the surface. It starts with simple rows and patterns of holes. Rectangular pockets to hold lamps, glass plates or other wooden inserts are just as easy to do.
Protruding edges face milling
Formatting is the third machining option of a face milling machine. This is used to bring an irregularly shaped workpiece into an exactly right-angled shape. The guide rails are locked one after the other for exact angles. For this purpose, a simple locking bolt is attached to each rail on professional devices. The best thing about it is that the edge is not only milled flush with the surface. In this processing step, any contour can be incorporated into the edge. All that is required is a cutter with a suitable profile.
Face milling of tree slices or end grain / end grain cutting boards
Tree slices or end grain have a star-shaped grain. This makes it a great challenge for grading. A planer would hit the grain parallel to the grain from the half of the board. This leads to cracks or breaks in the plate. Face milling is the better form of processing for leveling tree slices or end grain. The rapidly rotating cutter does not attack the wood horizontally, but in a vertical direction. As a result, the course of the grain is irrelevant for processing. Chipping, cracks and tears are thus reliably avoided.
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