Milling machines are among one of the most widely used machines in industries throughout the world. Being a remarkably versatile tool in the manufacturing industry, it is inevitable to deny its importance. Milling is a process in which a cutter with multiple cutting edges removes the material from the workpiece. Many surfaces, be it curve or flat, can be machined with accuracy and a good finish by milling.
A benchtop milling machine helps with better outputs in terms of precision and strength comparable to bigger machines. These are a mini version of those used in the milling industry and are preferably used by hobbyists and beginners for milling, cutting, flattening surfaces, and even drilling. Having know-how regarding the working principles of a milling machine can help one get the best out of it and that is why we are here to guide you through its functioning and requirements.
What You Will Need To Follow This Tutorial
For working with a milling machine, not much is required other than a workpiece, safety glasses, and a respirator. Following parts of the milling machine will be the ones most frequently used while performing tasks.
- Fine Feed knob: It either raises or lowers the spindle in fine increments.
- Downfeed Handle: It either raises or lowers the spindle in coarse increments.
- Spindle Rotation Buttons: When working in tapping mode, these buttons change the direction of spindle rotation and the direction can be reversed at any RPM in this mode, without stopping the spindle.
- Spindle Speed Readout: It displays the mode, spindle speed, RPM, and direction.
- RPM Dial: It is used for speed adjustment according to the required tasks.
- MILLING & TAPPING Switch: It selects the mode in which the machine is.
- Handwheels: These move the table in the X- and Y-axis.
- UP/DOWN Buttons: These are used to raise or lower the headstock.
- START Button: It starts the spindle motor for milling, tapping, and drilling operations.
- EMERGENCY STOP Button: It is used to emergency stop the mill and prevents restarting it while still in the depressed position. You can clockwise rotate the button to reset it.
- ZERO Button: It zeros the spindle scale at any point along its stroke.
- mm/inch Button: It toggles measurement units between metric and inch conventions.
- Tilt Arrows: Indicate the direction of tilt.
- Calibrate: It zeros the protractor at any position within the range of headstock tilt.
- HOLD: It locks the protractor at its current displayed value.
- Main Power Switch: It toggles power ON and OFF to the control panel of the machine.
Step By Step Guide
Step by step instructions are listed on how you can use a benchtop milling machine for a typical operation.
- Examining the workpiece: Ensure that the workpiece is suitable for milling.
- Put on safety gear: Remember to put on a respirator and protective glasses while working because using this machine without proper safety gear can cause harm to your lungs or eyes.
- Firmly clamp workpiece: The workpiece should be firmly clamped to the table to avoid it from slipping away during milling.
- Inspecting and installing correct cutting tools: Drills and end mills should be inspected before each use for sharpness, cracks, or chips. Replace blunt or cracked cutting tools with new sharp ones so the operations can be performed smoothly. Handle the cutting tools with care to avoid lacerations.
- Check the position of the workpiece and cutting tool: Ensure that the position of the cutting tool and workpiece is correct by using a manual downfeed and table controls.
- Setting digital depth stop: Set digital depth stop and mini digital protractor to the required units of measurement.
- Locking various parts: Lock the headlock and other required table locks in place.
- Determining speeds: Determine the feed rate and cutting speeds according to the milling task.
- Turn ON the machine: Connect your milling machine to power and turn ON the main power switch.
- Adjust spindle speed: Press “Start” and adjust spindle RPM using the spindle speed dial. The power needed for spindle rotation is obtained from the motor through the belt, gear, and clutch assembly.
- Perform the required task: Afterwards, you can begin milling, tapping, or drilling.
- Turn OFF the machine: Once you are done with the task, turn OFF the machine and disconnect the power supply.
A benchtop machine is an incredible tool and having one will bring many benefits and ease while working on multiple projects. Some of these have excelled by coming to use in big warehouses as well. These can be used to favor various tasks other than milling like cutting, thinning, grinding, and even slicing objects. Purchasing the right milling machine that suits your specific work type is very important as this invention is best for use when we are clear in the mind of the results we are trying to achieve through it.
What are the disadvantages of a milling machine?
Along with advantages, come some disadvantages too. Some of the downsides we found about working with milling machines include the following.
- Working with a milling machine accurately requires skills by the user.
- The size of the workpiece that is dealt with a milling machine is generally smaller.
- It is not suitable to work with castings and hot-rolled steels.
- These are expensive and not easy maintenance.
- The installation costs are not very economical.
- These use up a lot of electricity.
- High temperature is generated along with milling cutters while working.
- In many cases, they consume more space.
- Milling machines are not very good at radial cutting.
- The operator should have competency in controlling levels and be skilled to get the readings and instructions carefully.
Should I get a mill or a lathe?
Both a milling machine and a lathe are used to remove material from a workpiece and while the difference lies in the working principles of each. A milling machine works by rotating a multi-bladed or pointed cutting tool through a workpiece while a lathe works by rotating a single-bladed cutting tool through a workpiece.
It always depends on your work type that which tool you will be using. Some works are easier to get done on a milling machine comparatively while others are feasible to be worked with a lathe. But if you are a beginner and want to practice, the lathe is a better option as it seems more forgiving to learn with and comes in handy in comparison to a milling machine for this purpose. A lathe is also an elegant tool that teaches you a lot about cutting and gives margin while doing so. A general progression for a beginner can be from a sharpener to a lathe and then a milling machine.
Can you use a mill as a lathe?
Yes, a mill can be used as a lathe but in a pinch for small parts (under ¾”). Using it as both the tools is not a smart option because the mill bearing will become prone to wear out much faster. Therefore, it is better to use a dedicated machine or tool for a specific task because only a purpose-built tool will benefit your tasks.
What is a mini-mill?
A mini-mill is a smaller version of a full-size milling machine. It allows you to sit on a workbench and table while working its way through a workpiece. It is suitable to work with wood, metal, and even composite material components. These machines generally have a vertical orientation with the axis of a rotating shaft that is also vertical while the full-size mill machines have both vertical and horizontal in orientation. A milling machine comprises a stationary cutting tool and a movable table that is either manually or digitally controlled. A workpiece that we work on can be clamped to the table which moves around the rotating blade for it to make desired cuts on this piece.
Can a drill press be used as a mill?
A drill press is also known as a drilling machine is used to make holes in a workpiece. A milling machine can also do so while being able to cut that piece as well. This is the major difference between the two. Therefore, a drill press can be used as a mill machine but it will not be as efficient as a real one since it is not designed for this specific purpose. So it’s a better idea to purchase a real mill rather than converting other tools to become one.
The major difference is speed and most routers run 20,000 RPM while a drill machine will run only 600 to 3000 RPM. This is a big difference that is non-negligible therefore trying to convert a drill press into a milling machine might perform the desired small-scale task but can reduce the efficiency of the drill press in itself.
How many types of milling machines are there?
Milling machines are available in various types in the market based on their specifications. Some commonly known and used types are following:
- Column: The most commonly used type is a column milling machine. It has 5 basic components that include worktable, saddle, knee, overarm, and head. This is considered the easiest type to work with. Its cutting tool is vertically suspended allowing drilling off the metals. A column milling machine is generally used in creating car parts as they are handy and small.
- Turret: It is also known as a Bridgeport-type. The variety of operations that it can perform in addition to car parts make it versatile. Another feature that makes it very functional is that it can be repositioned anytime you want.
- C-frame: This type is more famous in the industrial setting as it is comparatively sturdy than few others like a turret. The presence of a hydraulic motor makes it more powerful.
- Horizontal: This type of milling machine works by running parallel to the ground. The table on which the workpiece is placed moves sideways while the cutting tool/device moves up and down.
- Bed type: In this type, the worktable is placed on the bed itself instead of being placed in its usual position, the top. The knee part is eliminated in this type to allow for the movements in longitudinal directions.
- Planer-style: This is similar to the bed type with a difference in the cutters and heads that enable a wider range of milling operations.
- Tracer controlled: This type is based on the master model hence has the ability to reproduce parts. The automotive industry generally opts for this type because it is easier to produce and specialize parts with it.
With multiple types of milling machines, each capable of performing specific tasks respectively, it becomes very important to purchase a type that suits your working type. You don’t necessarily have to buy the most heavy-duty milling machine, only a machine that is compatible with your working needs will allow you to work efficiently and provide maximum benefits.
Can you use a milling machine on wood?
Wood is one of the most versatile materials while learning to work with the machine. It is faster to work with and cheap as well. Being softer material, it is quite forgiving in terms of speed and feeds. You can practice detailed finishes and cuts while rough finishes can easily be managed with sandpaper. Being easy to stain and paint, it allows for interesting finish work by painting and subtly milling away afterward.
While being easy to machine, working with wood has some downsides as well. Cleaning up the mill after working becomes quite a task. When working with aluminum or steel chips, these get welded into the machine whereas wood becomes sand-like and gets everywhere. If you shop-vac your cabin immediately after working then it isn’t too bad but if you are occupied with many tasks and don’t get the time for simultaneous cleaning then it can become a major problem. Sometimes wood workpiece is very inconsistent and only a slight hit at the knot can cause breakage of the piece.