File Name: deburring and edge finishing handbook .zip
Burrs continue to be a significant issue for part manufacturers, but it is not just the burr that is the issue. Edges must be configured as either sharp, broken or have a radius to a specified tolerance.
- Burr (edge)
- Top finishers: Solutions for 10 of the most challenging deburring applications
- Burr (edge)
In addition to mechanical deburring, turbo-abrasive machining provides benefits including isotropic surfaces, improved profiles, and beneficial compressive stress. Turbo-Abrasive Machining [TAM] is a mechanical deburring and finishing method originally developed to automate edge finishing procedures on complex rotationally oriented and symmetrical aerospace engine components. Since its inception this method of utilizing fluidized abrasive materials has facilitated significant reductions in the amount of manual intervention required to deburr large components.
Deburring is a necessary evil. Nobody wants it but yet employees in most metal and plastics processing companies fight to master theses tasks on a daily basis. Therefore, deburring is rarely paid enough attention, as it does not directly add value. We at gravostar Technologies have been dealing with this topic on a daily basis for more than 25 years. In , we started to develop tools for milling deburring undefined edges integrated into the metal cutting process. Nowadays, this sector is one of our absolute core competencies.
In the following description, we will demonstrate how burrs form, why it is important to remove them and provide an overview of the different deburring procedures. Burrs that occur when casting metals ferrous or non-ferrous in the sand casting, chilled casting or pressure die casting procedure are indicated particularly by material residues that escape at the mould joints.
The same or similar after-effects also often occur when cutting or die pressing. The same problem sometimes also occurs when manufacturing plastic parts, in the injection die casting and the pressing procedure. Burrs are formed especially when machining parts turning, milling, drilling, sawing, etc. Burrs are also formed when cutting parts to size or separating them via water jet, laser, plasma or flame cutting. Molten material residues can remain stuck on the edges especially when plasma or flame cutting metals.
Burrs that are not removed often pose a massive risk of injury when handling parts cuts, etc. Furthermore, workpieces with burrs cannot be processed further in an optimum manner or are completely unusable.
Last but not least, a burr that later falls off can impair the functions of machines or systems, or even cause a complete failure.
The absolute worst case scenario that would result from this: recalling entire machine or vehicle series. The table below provides an overview of the most common methods for deburring workpieces.
The top two methods have a significant difference when compared to other procedures: deburring is fully automated without manual intervention, i.
This saves staff costs on the one hand and increases process reliability on the other. This procedure is particularly suitable for part production in CNC machines. The deburring procedure is an integrated part of the machining process. As with all other machining tools, the required deburring tools are stored in the tool magazine and are inserted automatically by the tool changer. Deburring completely machined parts with clearly defined edges is a well established process nowadays in most cases and is normally no longer questioned.
This means, it is normal that the parts are of course deburred automatically on the CNC machine using a chamfer milling cutter. This paints a vastly different picture: in this case, the relevant parts are very often deburred in a separate work step, and it is even common that this is done manually. Various tools have been available for deburring hole outlets for some time, which is why we will not deal with this topic extensively here.
Apart from this exception, it was not possible until the early s to deburr workpieces with undefined edges on the CNC machine. At least not if the requirement that all workpiece edges are to be deburred evenly despite size or position differences is to be met. In , this shortcoming was rectified: the world first engraflexx EC was presented: the first deburring tool driven via the machine spindle with a deflectable spindle.
This enables the workpiece edges to be deburred evenly, even if the programmed contour deviates from the effective workpiece contour. Nowadays, the corresponding deburring tools are available in two different deflection processes:. One version or the other is preferable depending on the actual application or requirements for the deburring result.
Both versions provide virtually the same results in different applications. The moveable tool spindle is held in the defined initial position at idle using a spring assembly:. In general, solid carbide router bits are used as the actual milling tools, as used in handheld pneumatic grinders. Due to the spring-loaded, pre-tensioned, flexible spindle mounting, this is simply pushed away by the router bit when following workpiece areas with different masses.
As the router bit always presses against the workpiece edge with the same force, it is deburred automatically and evenly everywhere. The process can be compared with the process in which the employee deburrs the workpiece manually using a pneumatic grinder. But this step is performed automatically in the CNC machine. The deburring contour can be programmed very easily: the theoretical workpiece contour is programmed first.
This is an alternative that is often used on CNC machines. There differences when compared to milling deburring are as follows. When deburring with brushes on CNC machines, we recommend using steel brushes that are tensioned in an adjustable, spring-mounted holder.
This procedure is for surface refinement, which is based on the classic procedure. These processes are normally performed in machines or systems designed especially for this. However, with the right tool equipment spring-mounted spindles , this work can also be performed using CNC machines. Finishing shapes and tools, polishing turbine blades, etc. If abrasive grinding agents are used for this, the machine and coolant contamination must be considered, in the same way as for deburring..
Remark: it is absolutely amazing how the surface can already be improved by using simple steel brushes that are clamped in a spring-mounted tool holder. In this process, deburring is performed in a downstream, separate work step regardless of part production or machining. This is performed in specially designed deburring systems or machines, which are often located in separate deburring areas designed especially for them.
In slide grinding, the workpieces to be machined are moved into a container together with abrasive products known as chips and normally with an additive into an aqueous solution as bulk goods. Therefore, in slide grinding, defined deburring does not take place but rather all workpiece surfaces that come into contact with the abrasive products are ground minimally and the edges rounded.
The abrasion performance and therefore the degree of deburring can be varied almost infinitely due to the selected abrasive products and additives, as well as the system runtime. This also known as explosion deburring is performed by packing the workpieces into a sealed combustion chamber. An oxygen mixture is then fed into the combustion chamber and ignited. This procedure is used particularly for workpieces with internal burrs, where mechanical deburring is not possible due to the inaccessibility.
In water jet or high pressure deburring, a water jet with a pressure of several hundred bar is guided onto the location to be machined, causing the protruding burrs to be separated. This procedure is particularly suitable for workpieces with locations that are difficult to access.
In this electrochemical deburring procedure, targeted material removal is enabled by anodic material break-up. This deburring procedure is particularly useful wherever hole transitions have to be rounded in a targeted manner, such as on distribution units for hydraulic systems.
The actual deburring procedure is normally performed using a deburring tool by milling, brushing or grinding here. A robotic deburring system can basically be laid out according to the following two designs:. Depending on the respective deburring tasks, different deburring units or tools are used. These can either be attached to the robot, the system or installed on the ground as described above.
The following is a selection of typical deburring units or tools for robotic systems:. If different deburring tasks are to be performed with different spindles or units on large workpieces, there is the option of equipping the robot with a tool changing unit.
This enables the robot to collect the required unit from the tool magazine and to put it back after use. One characteristic is that there are often small or large deviations between the deburring tool and the workpiece edges to be deburred.
There may be different reasons for this:. For this reason, deburring tools with deflectable spindles are normally used for deburring tasks. These are often complete units with an integrated drive spindle, which are stored flexibly in the housing. For a long time, these types of spindle units were only offered with an integrated compressed air spindle. Deflectable spindle units with electrical spindles generally high frequency spindles have been available for several years.
The electrical spindles are significantly more economical in comparison to spindles driven by compressed air, particularly with regard to the running costs energy consumption and maintenance costs see the following table. As actual deburring tools , solid carbide router bits of different sizes and shapes are used. Particularly when using in flexible deburring spindles, the deburring result depends significantly on selecting the suitable deburring tool. For this reason, it is important to work with the supplier that delivers the suitable tools in addition to the deburring spindles.
Of course, this also includes the corresponding technical support. In other words, the optimum supplier does not just sell tools but offer their customers a complete solution to the problem. There is an almost endless number of deburring brushes available on the market.
There are also many specialists who offer individually designed, customer-specific special brushes. All are justified, as the requirements for deburring brushes are very varied. However, a relatively simple measure can be taken to simplify the complexity of deburring brushes: clamp the brush into a spring-mounted tool holder rather than rigidly. If this also has an adjustable spring pre-tensioning force, a standard brush can often be used to achieve deburring results that you could never dream of.
The reason: the spring force no longer has to be applied by the brush but it is adjusted individually to the required dimension on the tool holder. At the same time, wear compensation is also included and the pre-tension pressure is always the same regardless of the wear to the deburring brush. This procedure is for surface refinement. These processes are very often performed in machines or systems designed especially for this.
However, with the right tool equipment spring-mounted spindles , this work can also be performed using robots. This procedure is still very widespread even today. Depending on the material, workpiece shape, severity of the burrs, etc. The requirements for high-quality manual deburring are often underestimated. In particular, as the work is rather unattractive, noisy and causes dirt, but still requires high concentration and lots of technical skill. Small deburring jobs are often performed in conjunction with part machining by the machine operator directly next to the machine.
If more time is required or more complex contours have to be processed, this is normally performed in separate deburring departments. Our core competence is in the area of mechanical deburring procedures that are integrated into the machining process directly on the CNC machine or immediately afterwards using robots. By passing on this experience, we wish to help interested users to optimised their deburring process sustainably.
Top finishers: Solutions for 10 of the most challenging deburring applications
Deburring is a necessary evil. Nobody wants it but yet employees in most metal and plastics processing companies fight to master theses tasks on a daily basis. Therefore, deburring is rarely paid enough attention, as it does not directly add value. We at gravostar Technologies have been dealing with this topic on a daily basis for more than 25 years. In , we started to develop tools for milling deburring undefined edges integrated into the metal cutting process.
Deburrs metal sheets and parts cut by laser, shear or punching machine. Deburring and edge rounding of straight parts at both sides in one single pass. Automatic and compact version available.
The Fierde is a deburring machine especially designed for processing small workpieces with a width up to mm. The Fierde features a brush height tracking system designed by Q-fin. Because of this,
There are several definitions for burrs, but they all describe the same phenomenon. Burrs are undesired but mainly unavoidable. A burr is a material accumulation, which is created on the surface during the manufacturing of a workpiece. It extends over the intended and actual workpiece surface and has a slightly higher volume in comparison with the workpiece Beier Burrs are uncut material remaining on the workpiece after being machined.
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