The Ultimate Guide to Proper Part Finishing
The Ultimate Guide to Proper Part Finishing
The manufacturing process of a part doesn’t stop when fabrication ends. There are still several steps it has to go through before it is ready for use. One of those steps is deburring.
This process is a key step in the finishing of a fabricated component for a prototyping manufacturing company. Its benefits go past just the increased visual appeal it offers. Proper deburring ensures the safety, durability, and even the proper fit of the parts.
RapidDone is an experienced prototyping manufacturing company, we accumulate huge experience in this process. We like to share.
In this article, we are going to talk about proper part deburring. We’re going to go over the what, why, and how of this process.
So, let’s dive in and start with a simple question “What is deburring?”.
What is Deburring?
Burrs occur in almost all machining processes, and they have a significant impact on the final part. To understand this process, we first have to define what burrs are.
What are Burrs?
Burrs are tiny imperfections that form and remain on the surface of a workpiece after machining, welding, or any fabrication process. They can be anything from raised surfaces to sharp edges on the workpiece’s surface.
Burrs come mainly in three forms. They are:
√ Rollover Burrs
Rollover burrs come in the form of curled-up bits of material projecting up from the part’s surface. They form when a cutting tool exits a material. They are the most common type of burrs.
√ Breakout Burrs
These are burrs that look like they are swelling out of the workpiece. They form due to the force exerted by the machine on the machine.
√ Poison Burrs
Poison burrs form when too much material collects at the end of the workpiece. It happens when a cutting tool’s edge extends beyond the workpiece. They occur as tiny bits of metal that extend sideways from the workpiece.
These imperfections compromise the look and quality of the final product. So, we need to remove them to get the best product quality possible.
In a word, it is the process of removing these burrs from the workpiece. It involves removing the material residue and imperfections from the manufactured component, creating a smooth quality part.
How are Burrs Formed?
Burrs that appear on a part during manufacturing can come from many sources. They can form during any stage of production and are the result of many factors.
Let’s go through some of the factors that affect burr formation.
√ Manufacturing Process Used
The type of manufacturing process a machinist uses plays a large role in burr formation. Plastic deformation of the workpiece and material deposition and solidification on the workpiece during manufacturing can cause burrs. Examples of manufacturing activities that can form burrs are machining processes like CNC Milling, CNC Turning, and drilling. Cutting processes like stamping, punching, laser cutting, etc. can also contribute to burr formation.
√ Material Selection
The part’s material also influences burr formation to a certain degree. Thin ductile materials are often easier to work with, leading to fewer burrs. Brittle, thick materials can present some difficulty leading to more burrs.
√ Operator Skill
Operator skill influences a lot in the manufacturing process. A skilled, experienced operator will know the proper precautions and machine configurations to keep burrs to a minimum. On the other hand, an inexperienced operator can make mistakes that lead to more burrs. Normally, an prototyping and low-volume manufacturing shop has some experience in this regard.
Why Do We Need Deburring?
Deburring is a necessary part of the product manufacturing process. Apart from enhancing the visual appeal of the product, it also offers a lot of benefits.
Examples of the benefits offered are:
√ Improved Part Safety
Components with burrs can pose a safety hazard to the people handling them. The sharp raised edges can pierce or slice skin even with proper gloves. With deburring, all these hazards are taken care of, leading to increased safety in the workplace.
√ Easy Component Assembly
Burrs can adversely affect the fit of a part in an assembly. The raised edges can interfere with the precision of the fit. So, for all the components to fit correctly, it’s important to deburr them properly.
√ Reduced Risk of Wear and Fatigue
Burrs on the surface of a part can cause undue friction and wear. They can also serve as points of crack propagation if they are located at certain corners and edges. It’s important to deburr to prolong the life of the parts.
How Is Deburring Done?
There are many methods available for handling burr parts. To choose a proper deburring process, you have to factor in part size, part complexity, and batch size.
Some of the methods are:
1. Hand (Manual) Deburring
Manual deburring involves using small hand tools like files, scrapers, deburring knives to remove the burrs on the workpiece. It is a time-consuming method, and its efficiency depends on the skill of the operator.
This method is what we use for small, complex parts. Small parts like this can easily get damaged if other high-powered methods are used. Also, most other methods may be too costly for the small components or batches.
2. Mechanical Deburring
Mechanical deburring tools use high-powered machine tools to deburr the workpiece. These machines remove the burrs from the workpiece using various abrasive processes. These abrasive processes come in many forms and they have varying degrees of efficiency.
Examples of mechanical methods include.
The tumbling method is used for deburring a high volume of parts simultaneously. It involves placing the part in a barrel with abrasive media. The technician can add water and some other compounds depending on the material.
A motor rotates the barrel causing the abrasive media and the parts to rub together. The friction generated by this motion abrades the part, deburring it in the process.
Brushing uses a special type of brush made out of abrasive materials to remove burrs. Brushing can be done either manually or with a machine. In this context, we are concerned with machine deburring.
The brush is mounted on a rotating machine spindle. The operator brings the workpiece near the brush. As the brush spins, it abrades the burrs away from the surface of the workpiece.
Brushing is a cost-effective method. It covers a large surface area and results in a smooth surface finish.
√ Hole Deburring
Hole deburring, as the name implies, involves removing burrs from a workpiece with a circular or cylindrical geometry. It requires different tools from normal deburring due to the circular geometry.
It involves mounting a cutting tool on a rotating spindle. We then carefully pass the spindle through the hole to smooth out the burrs.
Grinding can also be of use as a cost-effective method. We can use precision grinding machines to abrade burrs off the part and give it a smooth finish.
3. Thermal Deburring
This method uses heat to remove or burn off burrs from the workpiece. The process starts by sealing the workpiece in a pressurized chamber. A combustible mixture of oxygen and natural gas is introduced into the chamber.
The mixture is ignited and allowed to burn for a short period. During this time, the burrs on the surface are burnt off or oxidized. Note, due to the short burn time, the workpiece is not affected in any way.
Thermal deburring is great for handling complex parts with hard-to-reach corners and crevices. This is due to the gas which finds its way into all the open spaces in the part.
4. Electro-Chemical Deburring
In electrochemical deburring, the mechanism for burr removal is quite similar to that of electroplating. The workpiece forms the anode, while the deburring tool forms the negative cathode.
As an electrolyte circulates between both of them, the negatively charged cathode attracts and removes the burrs from the anode’s (workpiece) surface. The burrs dissolve in the electrolyte. They can be filtered out later.
Some things to note:
- Electrochemical deburring only works with corrosion-resistant metals.
- The shape of the cathode (deburring tool) determines the final shape of the workpiece. It influences the direction of the material removal process.
5. Cryogenic Deburring
Cryogenic deburring uses super-low temperatures to freeze burrs and aid in their removal. It is a cost-effective method for burr removal that results in high-quality finishes. It is employed with plastics and a few select metals.
It involves freezing the part to a cryogenic temperature where the burrs become brittle. The part is then impacted with abrasive media using a method like tumbling to remove the burrs.
Tips for Deburring Metal Parts
To achieve proper finishing, there are some tips you need to follow. Here are some of those tips:
√ Only Remove Burrs When and Where Necessary
Deburring is a process that can significantly add to the part’s final cost. To save time and cost, only deburr place where burrs can affect the safety and functionality of the product.
√ Use Automatic Deburring for Consistent Results
Manual deburring can be helpful, especially when dealing with small complex parts. But on large operations, it’s always best to go with automatic methods for better speed and consistency.
√ Use Cutting Fluid When Deburring Metals
Deburring operations like grinding and brushing can generate a lot of heat from friction. It’s best to use cutting fluid to keep the heat down and avoid things like chattering and friction damage.
√ Be Careful When Deburring Metals with Surface Coatings
Some operations can affect the surface coatings of metal parts. It’s best to go with methods like rotary brushing that can deburr the parts effectively while having little to no effect on the surface finish.
Q1: Can other materials apart from metal be deburred?
A: Yes, other materials can be deburred. Deburring processes exist for a wide range of materials like rubber, plastics, ceramics, etc.
Q2: Does deburring affect the tolerance and surface finish of a part?
A: When deburring is properly done, it affects neither the surface finish nor the part’s tolerance. It all depends on the technician’s skill and the deburring method chosen.
Q3: Are there burr-free manufacturing processes?
A: Yes, there are manufacturing processes that produce burr-free parts. These include processes like 3D printing and casting.
However, after manufacturing, most of these parts still need to be machined or cut. So, burrs may still form on their surfaces.
It’s clear now that deburring is an important part of the process of getting smooth high-quality parts. Also, getting the perfect surface finish involves selecting the right deburring method, and a combination of skill and precision.
It all sounds a bit tedious, doesn’t it? Don’t worry, we can help you with that.
At RapidDone, we choose not to limit ourselves to the fabrication and manufacturing of parts, covering both prototyping and mass production. We also provide world-class finishing services to ensure our clients get the best possible final product.
So, when you trust us with your projects, you can be sure that you are getting the best service possible. We will utilize all our experience and skill in making sure we churn out the highest quality product for you.
Contact us with your project today, and let us help you finish it the right way.