Monthly Archive May 31, 2022

Causes of over cutting of CNC machining parts

There are many reasons for workpiece overcutting in CNC processing. If the workpiece is overcutted, it will be processed after repair welding, or it will be directly invalidated. In particular, if the workpiece is overcutted during large mold processing, let’s share with you the work experience summarized in CNC processing

Hardware processing

If the workpiece overcut is programmed manually, it is caused by forgetting to take the tool radius into account in the programming. If it is software programming, it may be the selected tool alignment rather than tangency. These two programming methods will lead to the workpiece overcut.

  1. There is also a fault in tool selection for over cutting of machined parts. For example, a milling cutter with a diameter of 16mm is used in the program, but the result is a milling cutter with a diameter of 20mm. Although the difference between 4mm and 4mm is not big to the naked eye, all the machined parts will become smaller. This requires carefully checking whether the tool diameter is reasonable before machining, and don’t take chances.
  2. Another reason for workpiece overcutting is that the workpiece coordinate system input is wrong when zeroing. Be sure to remember to offset the radius value of a zero bar. The input error of tool compensation, tool length and tool radius compensation must be input correctly. If the input length of tool length is 0.5mm, the workpiece will be 0.5mm more. For large workpieces, they can’t be used directly. Whether the tool radius compensation is positive or negative should also be considered before tool compensation, Otherwise, it will also lead to over cutting of the workpiece.

The above are the reasons for overcutting of several common machining parts. Others, such as loose spindle and low precision of ball screw, will cause overcutting in the machining process. After overcutting, check the reasons in time to prevent similar situations from happening again.

ken. tang@chengcg.com

Classification of RC model vehicles

Like real cars, RC model cars will be divided into many types according to speed, climbing ability and off-road performance. Here we mainly introduce two types of model cars, off-road model cars and peace cars

Running a model car;

Type I off-road model vehicle

The commonly seen models in China can be roughly divided into: Baja, short haul truck, desert truck, racing truck, Bigfoot, competitive off-road vehicle and climbing vehicle;

Baja model

The Baja model car is characterized by simplicity, firmness and violence. The word “Baja” comes from an off-road vehicle race across the BAHA desert in Mexico. The Baja model car was first developed by HPI in the United States. Among them, HPI Baja 5B car opened the era of 1:5 gasoline car. Most of the Baja models are 2WD. The Baja 5B looks beautiful and rough;

Short haul truck

RC short course truck (RC short course truck), also known as remote-controlled field truck, is referred to as “short truck”. Compared with the Bigfoot truck, the short truck has small ground clearance, short suspension travel and small tires, and its trafficability is not as good as that of the Bigfoot truck. However, on the cross-country racing track, it can perform well, with faster speed, lighter body, flexible control and relatively low maintenance cost;

monster

The full name of the Bigfoot is RC monster truck. Although the speed and handling of the Bigfoot on the cross-country race track are not as good as the short truck and Baja models, don’t underestimate the speed of the Bigfoot. It can be completed within 3 seconds after accelerating 0-75km / h, which is worthy of the name of “monster truck”;

Competitive off-road vehicle

Competitive off-road vehicle is actually a model designed separately from RC model vehicle. At the beginning of its design, in addition to off-road performance, another design feature is that under reasonable control, the body can land relatively smoothly and undamaged in the state of high-altitude leap. Many players specially use competitive off-road vehicles to perform extreme high-altitude leap stunts;

Racing truck

The racing truck evolved from the competitive off-road vehicle. The most intuitive description of the racing truck is the big spider truck lying on the ground and moving quickly. Under the condition of high speed, the body of the racing truck will rise higher than the tire height with the speed, so as to maintain a better driving attitude and trafficability;

Climbing car

RC crawler is not famous for racing, but mainly for conquering rugged and dangerous road conditions;

Desert truck

Desert trucks are similar to short haul trucks. Their chassis is generally modified from traditional off-road vehicles;

The second type of flat running model car

The biggest difference between the flat running model vehicle and the off-road model vehicle lies in the different requirements on the road conditions. The flat running has strict requirements on the road conditions, because the flat running needs speed or continuous drift action, while the off-road has little requirements on the road conditions. The more complex the road conditions are, the more wild the flavor can be played;

Level running model cars are generally divided into three types: Racing level running, drift and street car;

Racing flat sports car

If you are a radical who has a serious obsession with acceleration performance, you can choose this kind of model. In order to achieve amazing speed, the requirements of racing flat running on the road are relatively harsh. Another feature is the design of car shell. Most of the simulated car shell of racing flat running of model manufacturers must be authorized by major automobile manufacturers, so the simulation degree of general racing flat sports car will be relatively high;

Drift vehicle

Drifting RC car (drifting RC car), for short, beginners can immediately experience the pleasure of driving a racing car drifting by Fujiwara Tuohai in the first character d with a little practice, but the drifting car is also the most technical and difficult in RC. It takes a lot of practice to complete accurate drifting and turning;

trolley

Street cars, as the name suggests, can run on ordinary roads, but their ability to adapt to the road can not be compared with cross-country models. After all, the suspension and chassis design of street cars are more biased to the need of speed;