CNC Machining, CNC Turning, CNC Milling-CHENGCHUANG Limited

Bychengcg

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;

Bychengcg

How to improve surface finish in CNC machining

In terms of size, the parts meet the blueprint specifications, but the surface finish and overall appearance are not ideal? What should we do?

Consider the following options:

  1. Control chip: chip evacuation is the key factor to produce good surface finish. Control chip may be the first thing you should consider. If the produced chips come into contact with the workpiece during machining, or if you are re cutting the chips, it is likely to affect your surface finish in a negative way. Consider the possibility of changing the style of the chip breaker you are using to help disassemble the chip for better control.

Although using air and coolant is a good choice to control chip removal, pay attention to coolant. Avoid using coolant when cutting intermittently. Hot cracks on the cutting edge will occur Due to intermittent heating and rapid cooling of cutting edges And it can lead to premature blade failure, or at least start to affect your surface finish because of over stressed cutting edges and failure.

  1. Improve speed: This is especially true when using cemented carbide tools. Increasing the speed will ensure that the contact time between the material and the tool tip is shorter Therefore, the edge accumulation on the tool is reduced, which may lead to poor surface finish. Increasing the rake angle of the cutting tool also helps to reduce and control edge accumulation.
  2. Use the correct tip radius: a larger tip radius will be able to adapt to a faster speed. The insert can feed at about half of TNR per revolution and still produce good results. If you exceed this TNR to IPR ratio, the tool will create more “linear” surface finish than the glossy smooth surface you want. Therefore, the larger the TNR, the faster the feed speed it can accommodate and still produce the desired results. However, using a very large TNR can produce chatter – reduce cutting pressure – so be careful and consider the speed required to cut the material – use a TNR tool that meets your needs.

It is also worth mentioning that using a larger tip radius means that you must leave more material for completion. To ensure proper operation of the tool, you must set TNR equal to or greater than TNR in order to complete the removal of the tool.

When milling, try to use fillet or spherical end milling cutter instead of plane end milling cutter. Something with a rounded radius will give you a higher finish at sharp corners and will certainly help extend tool life.

  1. Try to insert the wiper: as far as possible. The wiper insert has a small flat area adjacent to the tip radius. When the tool is fed along the workpiece, this plane actually “wipes” the finish and helps eliminate the linear finish that may be encountered at a faster feed rate – this allows the use of a smaller TNR to help control chatter.
  2. Increase the lead angle of the tool. Higher lead angle and positive tilt blades produce better surface finish than tools with shallow cutting angles. For example, a face milling cutter with a 45 ° cutting angle will produce a better surface finish than a face milling cutter with a 90 ° cutting angle.
  3. Eliminate dwell and pause: every time the tool stops moving when it comes into contact with the surface of the part, it will leave traces. Change the process if necessary, but try to ensure that the tool never stops or hesitates during the cutting process.

ken. tang@chengcg.com