Selecting correct tolerance for machined components

Concerning the tolerance of machined components. 

Generally, the dimensional tolerance is determined first.

And then the shape and position tolerance is determined. When we design the machined components, for the reasonable tolerance, we should consider the function needs first, the second is the processing technology.

The last is the assembly and maintenance technology.

For example, assembly hole and shaft, it is not only a round hole and shaft, can be square,but we usually use round, because the convenient processing. Traditional processing methods such as turning, milling, drilling and grinding,most of the circular processing. Now with the popularity of laser cutting and wire cutting,the application of special-shaped hole is also more.At the same tolerance level,the processing cost of square hole is higher than round hole.

Since the traditional method of processing is circular processing, the choice of hole and shaft will have a basic hole system and basic shaft system.

Generally, we can get hole by drilling, reaming, and milling. For convenient machining, we should choose to have readily available tools (drill, reamer,cutter) size, such as the diameter 14mm of cutting tool are very rare, we can choose 12mm,15mm or 16mm diameter of cutting tools,which is a conveninet purchase specifications. In this way, the manufacturing cost is very low. For example,choose diameter 30mm not 27mm, although your computing needs 27mm.

The fit of hole and shaft includes clearance fit, transition fit and interference fit.

Learn more about tolerance of machined components.

Advanced CNC machining parts factories

Advanced cnc machining parts factories have lots of cnc machine,they have advanced technologies.They always can produce superior quality machined parts.That's because they are proficient in the methods and skills of CNC machining.

1.Programming skills

The demand of CNC machining parts is very high.there are two aspects should be fully considered when programming.

One is the processing sequence,and the other is parameters such as speed,feed,and depth of cut.

The processing sequence is generally drilling first, then flat end. This can prevent material shrinkage during drilling. Rough machining first, then precise machining.First machining with large tolerances and final machining with small tolerance.

According to the hardness of the material,choosing a reasonable speed, feed and depth of cut.

Carbon steel materials: choosing high speed,high feed,and large depth of cut.

Carbide materials: choosing low speed,low feed, and small depth of cut.

Titanium alloys materials: choosing low speed, high feed, and small depth of cut.

2.Direct tool setting method

First select the center of the right end of the machined part as the tool setting point, and set it as the zero point.After the machine tool returns to the origin, each tool that needs to be used is set at the zero point.

This direct tool setting method, even if the machining center is powered off, the tool setting value will not be changed after the power is turned on again and restarted.

3.Debugging Tips

In order to prevent errors in the program and mistakes in tool setting,after the parts are programmed, they need to be tested and debugged after the tool is adjusted.

First, carry out simulation processing,and confirm that the program and tool setting are correct.

Second,processing the first part.

Finally,the debugging is over after confirming that the first part is qualified.

4.Tool collision prevention tips

The collision of the tool is a great damage to the accuracy of the equipment.As long as the operator is careful and know methods of anti-collision,collisions can be completely prevented and avoided.

There are only three reasons for tool collision.

1) The input error of the diameter and length of the tool.

2) The input error of dimensions of the machined parts and the initial position of the machined parts.

3) The machined parts coordinate system of the machining center is set incorrectly, or the machine zero point is reset in the machining process.

In order to avoid the collision above, the operator should pay attention more in machining process, observe whether the machine tool has abnormal movement, whether there is spark,whether there is burnt smell. If an abnormal situation is found, the program should be stopped immediately,and start to work after the problem is solved.

Choosing the Right Material for Aluminium Machined Parts

Choosing the Right Material for Your Aluminium Machined Parts.

There are many kinds of aluminium alloy in the market,only 7 kind aluminium alloy be used commonly for precision aluminium machined parts.


AL6061

The main alloy elements of AL6061 are magnesium and silicon, with moderate strength, good corrosion resistance, weldability and good oxidation.It is widely used in various industrial structures requiring high strength and antimicrobial resistance.
Generally the internal stress of T6 is bigger, the processing will be deformed, and the most suitable state should be T651.

AL7075

AL7075 materials are generally added in a small amount of copper, chromium and other alloys,It is reputed as the most excellent product in aluminum alloy, with high strength and far superior to any soft steel,Easy to process and good wear resistancee,but it can't be soldered and it's very anti-corrosive,it's better used with anodize.

Used for high - voltage structural parts,Such as aerospace, mould processing, mechanical equipment, tooling and fixtures industry.

AL6063

AL6063 material is a low-alloyed al-mg-si high-plastic alloy.It has excellent thermoplastic and can be extruded into complex structure at high speed,thin wall, Various shapes of hollow and forging parts.
Widely used in building aluminum doors and Windows, curtain wall frame,heat sink parts.

AL5083

AL5083 material is a high - magnesium alloy. It has good strength, corrosion resistance,weldability and cutting ability in non - heat treatment alloy,the surface is beautiful after anodizing.
Excellent corrosion resistance makes 5083 alloys widely used for marine applications such as ships and welding of automobiles and aircraft parts, subway light rail.

AL5052

5052 aluminum alloy belongs to al-mg alloy,with good corrosion resistance, good welding, good cold processing, and moderate strength.
Used to make aircraft fuel tanks, tubing, and traffic vehicles, the sheet metal parts of the ship,electric shell.


AL6082

AL6082 aluminum alloy belongs to Al-Mg-Si alloy,It has medium strength and good welding performance and corrosion resistance.Easy to process and easily coated.
Mainly used in transportation and structural engineering industries. Such as bridges, cranes, roof frames, transport aircraft,carrier etc.

AL2024
This is a high strength hard aluminum, which can be strengthened by heat treatment, and is of medium plasticity in quenching and quenching.Resistance to corrosion is not high, and anodizing treatment and coating method or surface are used to enhance the corrosion resistance.
It is mainly used to make all kinds of high-load parts and components (but not stamping parts) such as the skeleton parts on the plane.

Know more details please read SYM Blog.