Tag Archives: tractor wheel

China OEM Heavy Duty Large Power Plant Cargo Trailer Transport Full Wheel Drive 6X4 CZPT Tractor Head with LNG CNG Fuels with Good quality

Product Description

 SHACMAN DUMP TRUCK, Welcome to your inquiry.
The business scope involves all products traded by customers in Central Asia, mainly in the fields of machinery and equipment, heavy trucks and heavy truck accessories, cargo transportation.

Product Description

Anti-skid: Prevent the idling of driving wheels on wet and slippery roads, such as snow, so that vehicles can start and accelerate smoothly. Especially on snow or muddy roads, the traction control system can ensure smooth acceleration performance and prevent the vehicle from transverse movement or tail flick due to the slippage of the driving wheels.

 

Nimble: when driving a vehicle, it makes the motor train have better mobility and flexibility.

Reliable operation: ensure that the connection between traction vehicle and trailer is reliable, convenient and quick.

 

Smooth: the traction force can be transmitted to the trailer smoothly and buffering the impact load. Anti-skid: Prevent the idling of driving wheels on wet and slippery roads, such as snow, so that vehicles can start and accelerate smoothly. Especially on snow or muddy roads, the traction control system can ensure smooth acceleration performance and prevent the vehicle from transverse movement or tail flick due to the slippage of the driving wheels.

 

Nimble: when driving a vehicle, it makes the motor train have better mobility and flexibility.

Reliable operation: ensure that the connection between traction vehicle and trailer is reliable, convenient and quick.

 

Smooth: the traction force can be transmitted to the trailer smoothly and buffering the impact load.

 

Product Parameters

Company Profile

 

Packaging & Shipping

We supervise the process from the factory to the port designated by the customer to ensure that the customer’s products arrive at the destination accurately and safely.

Car components

Workshop environment
Sample products
Welcome to cooperate

 

CONTACT INFOMATION

After Sales Service

 we are famous building machinery manufacturer, professional construction machinery exporter and 1 stop solution supplier in China, our team have  more than 15 years experience in this field already. 

(1)Warranty:Every product issued shall enjoy a one-year/2000 working hour warranty period, during which we will repair or replace the defective parts free of charge if material or process defects occur and spare parts are in normal working condition.

(2)Spare parts:CANMAX is dedicated to provide our clients with genuine spare parts with the highest quality,exact fitness and appropriate function.with our global distributor network,you are guaranteed with fast deliveries and services, wherever you are,please submit your spare parts request to us,and list products name ,description of required parts.we guarantee that your request will be handled quickly and appropriately.

(3)Installation & Maintenance:CANMAX is CZPT to provide with the overall installation of complicated machinery,allowing you to start the normal operation of construction machinery solutions.After installation,we will make inspection of the whole machine,operate equipment,and provide you with testing data reports of installation and operation.

(4)Training:CANMAX offer perfect facilities and comfortable environment and can provide training services to different users. The training sessions include product training, operation training, maintenance know-how, technical know-how training, standards, laws and regulations training and other training, all of which are tailored to fulfill your individual needs. Training programs can be conducted in our factory field, or at the client’s site.

(5)Technical Advice: CANMAX can also help customers to coordinate with trained service personnel and provide you with detailed and extensive knowledge. Through our technical advice, your machine life can be significantly extended and sustained high capacity.

We have already exported our products to more than 80 countries and regions, including: Africa, the Middle East, South America, Central Asia, Russia, Mexico, Australia, New Zealand, Holland, British, Mongolia and so on. 

 

FAQ

— Which countries do you export to?

Asia: India, Philippines, Thailand, Burma, Vietnam, Bangladesh, Kazakhstan, Turkmenistan, etc. Middle East: Saudi Arabia,UAE, Jordan, Oman, Syria, Pakistan, Qatar, etc. Europe: Russia, Ukraine, Belarus, Bulgaria, etc. Africa: South Africa, Kenya, Congo, Ethiopia, Nigeria, Ghana, Algeria, Senegal, Tunisia, etc. South America: Brazil, Peru, Chile, Cuba, Venezuela, Mexico, etc. Oceania: Papua New Guinea, Australia, etc.

 –What is the proportion of your products exported?

75% of our products are exported to all over the world.

  –What is the payment term?

Payment term is negotiable and there will be favorable payment terms for long-term customers. TT, L/C, D/P, depending on the cooperation time, country and contract value.

  –What kind of logistic service do you supply?

A. Transportation: railway transportation, international through transport, including (international railway through transportation, Sea-rail intermodal through transportation, sea-land multimodal transportation. Means of transport : Container, LCL, FRC, ro-ro, bulk cargo, train carriage, truck, air plane.

B. Term: FOB,CIF, DAP, to door service, etc.

  –What spare parts can you supply?

All kinds of spare parts of SHXIHU (WEST LAKE) DIS.I, ZOOMLION, SINOTRUCK, SHACMAN, LIUGONG, SAN Y, SDL G, LONKING, XGMA, CZPT S ENGINE, ZF GEAR BOX, etc.

  —How about shipment?

20FT container, 40FT container,40FT high container,
open-top container,flat bed container ,Ro-Ro ship or bulk 
ship according to the size the products.

 

Analytical Approaches to Estimating Contact Pressures in Spline Couplings

A spline coupling is a type of mechanical connection between 2 rotating shafts. It consists of 2 parts – a coupler and a coupling. Both parts have teeth which engage and transfer loads. However, spline couplings are typically over-dimensioned, which makes them susceptible to fatigue and static behavior. Wear phenomena can also cause the coupling to fail. For this reason, proper spline coupling design is essential for achieving optimum performance.
splineshaft

Modeling a spline coupling

Spline couplings are becoming increasingly popular in the aerospace industry, but they operate in a slightly misaligned state, causing both vibrations and damage to the contact surfaces. To solve this problem, this article offers analytical approaches for estimating the contact pressures in a spline coupling. Specifically, this article compares analytical approaches with pure numerical approaches to demonstrate the benefits of an analytical approach.
To model a spline coupling, first you create the knowledge base for the spline coupling. The knowledge base includes a large number of possible specification values, which are related to each other. If you modify 1 specification, it may lead to a warning for violating another. To make the design valid, you must create a spline coupling model that meets the specified specification values.
After you have modeled the geometry, you must enter the contact pressures of the 2 spline couplings. Then, you need to determine the position of the pitch circle of the spline. In Figure 2, the centre of the male coupling is superposed to that of the female spline. Then, you need to make sure that the alignment meshing distance of the 2 splines is the same.
Once you have the data you need to create a spline coupling model, you can begin by entering the specifications for the interface design. Once you have this data, you need to choose whether to optimize the internal spline or the external spline. You’ll also need to specify the tooth friction coefficient, which is used to determine the stresses in the spline coupling model 20. You should also enter the pilot clearance, which is the clearance between the tip 186 of a tooth 32 on 1 spline and the feature on the mating spline.
After you have entered the desired specifications for the external spline, you can enter the parameters for the internal spline. For example, you can enter the outer diameter limit 154 of the major snap 54 and the minor snap 56 of the internal spline. The values of these parameters are displayed in color-coded boxes on the Spline Inputs and Configuration GUI screen 80. Once the parameters are entered, you’ll be presented with a geometric representation of the spline coupling model 20.

Creating a spline coupling model 20

The spline coupling model 20 is created by a product model software program 10. The software validates the spline coupling model against a knowledge base of configuration-dependent specification constraints and relationships. This report is then input to the ANSYS stress analyzer program. It lists the spline coupling model 20’s geometric configurations and specification values for each feature. The spline coupling model 20 is automatically recreated every time the configuration or performance specifications of the spline coupling model 20 are modified.
The spline coupling model 20 can be configured using the product model software program 10. A user specifies the axial length of the spline stack, which may be zero, or a fixed length. The user also enters a radial mating face 148, if any, and selects a pilot clearance specification value of 14.5 degrees or 30 degrees.
A user can then use the mouse 110 to modify the spline coupling model 20. The spline coupling knowledge base contains a large number of possible specification values and the spline coupling design rule. If the user tries to change a spline coupling model, the model will show a warning about a violation of another specification. In some cases, the modification may invalidate the design.
In the spline coupling model 20, the user enters additional performance requirement specifications. The user chooses the locations where maximum torque is transferred for the internal and external splines 38 and 40. The maximum torque transfer location is determined by the attachment configuration of the hardware to the shafts. Once this is selected, the user can click “Next” to save the model. A preview of the spline coupling model 20 is displayed.
The model 20 is a representation of a spline coupling. The spline specifications are entered in the order and arrangement as specified on the spline coupling model 20 GUI screen. Once the spline coupling specifications are entered, the product model software program 10 will incorporate them into the spline coupling model 20. This is the last step in spline coupling model creation.
splineshaft

Analysing a spline coupling model 20

An analysis of a spline coupling model consists of inputting its configuration and performance specifications. These specifications may be generated from another computer program. The product model software program 10 then uses its internal knowledge base of configuration dependent specification relationships and constraints to create a valid three-dimensional parametric model 20. This model contains information describing the number and types of spline teeth 32, snaps 34, and shoulder 36.
When you are analysing a spline coupling, the software program 10 will include default values for various specifications. The spline coupling model 20 comprises an internal spline 38 and an external spline 40. Each of the splines includes its own set of parameters, such as its depth, width, length, and radii. The external spline 40 will also contain its own set of parameters, such as its orientation.
Upon selecting these parameters, the software program will perform various analyses on the spline coupling model 20. The software program 10 calculates the nominal and maximal tooth bearing stresses and fatigue life of a spline coupling. It will also determine the difference in torsional windup between an internal and an external spline. The output file from the analysis will be a report file containing model configuration and specification data. The output file may also be used by other computer programs for further analysis.
Once these parameters are set, the user enters the design criteria for the spline coupling model 20. In this step, the user specifies the locations of maximum torque transfer for both the external and internal spline 38. The maximum torque transfer location depends on the configuration of the hardware attached to the shafts. The user may enter up to 4 different performance requirement specifications for each spline.
The results of the analysis show that there are 2 phases of spline coupling. The first phase shows a large increase in stress and vibration. The second phase shows a decline in both stress and vibration levels. The third stage shows a constant meshing force between 300N and 320N. This behavior continues for a longer period of time, until the final stage engages with the surface.
splineshaft

Misalignment of a spline coupling

A study aimed to investigate the position of the resultant contact force in a spline coupling engaging teeth under a steady torque and rotating misalignment. The study used numerical methods based on Finite Element Method (FEM) models. It produced numerical results for nominal conditions and parallel offset misalignment. The study considered 2 levels of misalignment – 0.02 mm and 0.08 mm – with different loading levels.
The results showed that the misalignment between the splines and rotors causes a change in the meshing force of the spline-rotor coupling system. Its dynamics is governed by the meshing force of splines. The meshing force of a misaligned spline coupling is related to the rotor-spline coupling system parameters, the transmitting torque, and the dynamic vibration displacement.
Despite the lack of precise measurements, the misalignment of splines is a common problem. This problem is compounded by the fact that splines usually feature backlash. This backlash is the result of the misaligned spline. The authors analyzed several splines, varying pitch diameters, and length/diameter ratios.
A spline coupling is a two-dimensional mechanical system, which has positive backlash. The spline coupling is comprised of a hub and shaft, and has tip-to-root clearances that are larger than the backlash. A form-clearance is sufficient to prevent tip-to-root fillet contact. The torque on the splines is transmitted via friction.
When a spline coupling is misaligned, a torque-biased thrust force is generated. In such a situation, the force can exceed the torque, causing the component to lose its alignment. The two-way transmission of torque and thrust is modeled analytically in the present study. The analytical approach provides solutions that can be integrated into the design process. So, the next time you are faced with a misaligned spline coupling problem, make sure to use an analytical approach!
In this study, the spline coupling is analyzed under nominal conditions without a parallel offset misalignment. The stiffness values obtained are the percentage difference between the nominal pitch diameter and load application diameter. Moreover, the maximum percentage difference in the measured pitch diameter is 1.60% under a torque of 5000 N*m. The other parameter, the pitch angle, is taken into consideration in the calculation.

China OEM Heavy Duty Large Power Plant Cargo Trailer Transport Full Wheel Drive 6X4 CZPT Tractor Head with LNG CNG Fuels   with Good qualityChina OEM Heavy Duty Large Power Plant Cargo Trailer Transport Full Wheel Drive 6X4 CZPT Tractor Head with LNG CNG Fuels   with Good quality

China Best Sales CZPT 6X6 All Wheel Drive Tractor Truck Head Low Price for Sale with Free Design Custom

Product Description

 SHACMAN DUMP TRUCK, Welcome to your inquiry.
The business scope involves all products traded by customers in Central Asia, mainly in the fields of machinery and equipment, heavy trucks and heavy truck accessories, cargo transportation.

Product Description

Anti-skid: Prevent the idling of driving wheels on wet and slippery roads, such as snow, so that vehicles can start and accelerate smoothly. Especially on snow or muddy roads, the traction control system can ensure smooth acceleration performance and prevent the vehicle from transverse movement or tail flick due to the slippage of the driving wheels.

 

Nimble: when driving a vehicle, it makes the motor train have better mobility and flexibility.

Reliable operation: ensure that the connection between traction vehicle and trailer is reliable, convenient and quick.

 

Smooth: the traction force can be transmitted to the trailer smoothly and buffering the impact load. Anti-skid: Prevent the idling of driving wheels on wet and slippery roads, such as snow, so that vehicles can start and accelerate smoothly. Especially on snow or muddy roads, the traction control system can ensure smooth acceleration performance and prevent the vehicle from transverse movement or tail flick due to the slippage of the driving wheels.

 

Nimble: when driving a vehicle, it makes the motor train have better mobility and flexibility.

Reliable operation: ensure that the connection between traction vehicle and trailer is reliable, convenient and quick.

 

Smooth: the traction force can be transmitted to the trailer smoothly and buffering the impact load.

 

Product Parameters

Company Profile

 

Packaging & Shipping

We supervise the process from the factory to the port designated by the customer to ensure that the customer’s products arrive at the destination accurately and safely.

Car components

Workshop environment
Sample products
Welcome to cooperate

 

CONTACT INFOMATION

After Sales Service

 we are famous building machinery manufacturer, professional construction machinery exporter and 1 stop solution supplier in China, our team have  more than 15 years experience in this field already. 

(1)Warranty:Every product issued shall enjoy a one-year/2000 working hour warranty period, during which we will repair or replace the defective parts free of charge if material or process defects occur and spare parts are in normal working condition.

(2)Spare parts:CANMAX is dedicated to provide our clients with genuine spare parts with the highest quality,exact fitness and appropriate function.with our global distributor network,you are guaranteed with fast deliveries and services, wherever you are,please submit your spare parts request to us,and list products name ,description of required parts.we guarantee that your request will be handled quickly and appropriately.

(3)Installation & Maintenance:CANMAX is CZPT to provide with the overall installation of complicated machinery,allowing you to start the normal operation of construction machinery solutions.After installation,we will make inspection of the whole machine,operate equipment,and provide you with testing data reports of installation and operation.

(4)Training:CANMAX offer perfect facilities and comfortable environment and can provide training services to different users. The training sessions include product training, operation training, maintenance know-how, technical know-how training, standards, laws and regulations training and other training, all of which are tailored to fulfill your individual needs. Training programs can be conducted in our factory field, or at the client’s site.

(5)Technical Advice: CANMAX can also help customers to coordinate with trained service personnel and provide you with detailed and extensive knowledge. Through our technical advice, your machine life can be significantly extended and sustained high capacity.

We have already exported our products to more than 80 countries and regions, including: Africa, the Middle East, South America, Central Asia, Russia, Mexico, Australia, New Zealand, Holland, British, Mongolia and so on. 

 

FAQ

— Which countries do you export to?

Asia: India, Philippines, Thailand, Burma, Vietnam, Bangladesh, Kazakhstan, Turkmenistan, etc. Middle East: Saudi Arabia,UAE, Jordan, Oman, Syria, Pakistan, Qatar, etc. Europe: Russia, Ukraine, Belarus, Bulgaria, etc. Africa: South Africa, Kenya, Congo, Ethiopia, Nigeria, Ghana, Algeria, Senegal, Tunisia, etc. South America: Brazil, Peru, Chile, Cuba, Venezuela, Mexico, etc. Oceania: Papua New Guinea, Australia, etc.

 –What is the proportion of your products exported?

75% of our products are exported to all over the world.

  –What is the payment term?

Payment term is negotiable and there will be favorable payment terms for long-term customers. TT, L/C, D/P, depending on the cooperation time, country and contract value.

  –What kind of logistic service do you supply?

A. Transportation: railway transportation, international through transport, including (international railway through transportation, Sea-rail intermodal through transportation, sea-land multimodal transportation. Means of transport : Container, LCL, FRC, ro-ro, bulk cargo, train carriage, truck, air plane.

B. Term: FOB,CIF, DAP, to door service, etc.

  –What spare parts can you supply?

All kinds of spare parts of SHXIHU (WEST LAKE) DIS.I, ZOOMLION, SINOTRUCK, SHACMAN, LIUGONG, SAN Y, SDL G, LONKING, XGMA, CZPT S ENGINE, ZF GEAR BOX, etc.

  —How about shipment?

20FT container, 40FT container,40FT high container,
open-top container,flat bed container ,Ro-Ro ship or bulk 
ship according to the size the products.

 

What You Should Know About Axle Shafts

There are several things you should know about axle shafts. These include what materials they’re made of, how they’re constructed, and the signs of wear and tear. Read on to learn more about axle shafts and how to properly maintain them. Axle shafts are a crucial part of any vehicle. But how can you tell if 1 is worn out? Here are some tips that can help you determine whether it’s time to replace it.

Materials used for axle shafts

When it comes to materials used in axle shafts, there are 2 common types of materials. One is carbon fiber, which is relatively uncommon for linear applications. Carbon fiber shafting is produced by CZPT(r). The main benefit of carbon fiber shafting is its ultra-low weight. A carbon fiber shaft of 20mm diameter weighs just 0.17kg, as opposed to 2.46kg for a steel shaft of the same size.
The other type of material used in axle shafts is forged steel. This material is strong, but it is difficult to machine. The resulting material has residual stresses, voids, and hard spots that make it unsuitable for some applications. A forged steel shaft will not be able to be refinished to its original dimensions. In such cases, the shaft must be machined down to reduce the material’s hardness.
Alternatively, you can choose to purchase a through-hardened shaft. These types of axle shafts are suitable for light cars and those that use single bearings on their hub. However, the increased diameter of the axle shaft will result in less resistance to shock loads and torsional forces. For these applications, it is best to use medium-carbon alloy steel (MCA), which contains nickel and chromium. In addition, you may also need to jack up your vehicle to replace the axle shaft.
The spline features of the axle shaft must mate with the spline feature on the axle assembly. The spline feature has a slight curve that optimizes contact surface area and distribution of load. The process involves hobbing and rolling, and it requires special tooling to form this profile. However, it is important to note that an axle shaft with a cut spline will have a 30% smaller diameter than the corresponding 1 with an involute profile.
Another common material is the 300M alloy, which is a modified 4340 chromoly. This alloy provides additional strength, but is more prone to cracking. For this reason, this alloy isn’t suited for street-driven vehicles. Axle shafts made from this alloy are magnaflushed to detect cracks before they cause catastrophic failure. This heat treatment is not as effective as the other materials, but it is still a good choice for axle shafts.
Driveshaft

Construction

There are 3 basic types of axle shafts: fully floating, three-quarter floating, and semi-floating. Depending on how the shaft is used, the axles can be either stationary or fully floating. Fully floating axle shafts are most common, but there are exceptions. Axle shafts may also be floating or stationary, or they may be fixed. When they are stationary, they are known as non-floating axles.
Different alloys have different properties. High-carbon steels are harder than low-carbon steels, while medium-carbon steels are less ductile. Medium-carbon steel is often used in axle shafts. Some shafts contain additional metals, including silicon, nickel, and copper, for case hardening. High-carbon steels are preferred over low-carbon steels. Axle shafts with high carbon content often have better heat-treatability than OE ones.
A semi-floating axle shaft has a single bearing between the hub and casing, relieving the main shear stress on the shaft but must still withstand other stresses. A half shaft needs to withstand bending loads from side thrust during cornering while transmitting driving torque. A three-quarter floating axle shaft is typically fitted to commercial vehicles that are more capable of handling higher axle loads and torque. However, it is possible to replace or upgrade the axle shaft with a replacement axle shaft, but this will require jacking the vehicle and removing the studs.
A half-floating axle is an alternative to a fixed-length rear axle. This axle design is ideal for mid-size trucks. It supports the weight of the mid-size truck and may support mid-size trucks with high towing capacities. The axle housing supports the inner end of the axle and also takes up the end thrust from the vehicle’s tires. A three-quarter floating axle, on the other hand, is a complex type that is not as simple as a semi-floating axle.
Axle shafts are heavy-duty load-bearing components that transmit rotational force from the rear differential gearbox to the rear wheels. The half shaft and the axle casing support the road wheel. Below is a diagram of different forces that can occur in the axle assembly depending on operating conditions. The total weight of the vehicle’s rear can exert a bending action on the half shaft, and the overhanging section of the shaft can be subject to a shearing force.
Driveshaft

Symptoms of wear out

The constant velocity axle, also called the half shaft, transmits power from the transmission to the wheels, allowing the vehicle to move forward. When it fails, it can result in many problems. Here are 4 common symptoms of a bad CV axle:
Bad vibrations: If you notice any sort of abnormal vibration while driving, this may be a sign of axle damage. Vibrations may accompany a strange noise coming from under the vehicle. You may also notice tire wobble. It is important to repair this problem as it could be harmful to your car’s handling and comfort. A damaged axle is generally accompanied by other problems, including a weak braking response.
A creaking or popping sound: If you hear this noise when turning your vehicle, you probably have a worn out CV axle. When the CV joints lose their balance, the driveshaft is no longer supported by the U-joints. This can cause a lot of vibrations, which can reduce your vehicle’s comfort and safety. Fortunately, there are easy ways to check for worn CV axles.
CV joints: A CV joint is located at each end of the axle shaft. In front-wheel drive vehicles, there are 2 CV joints, 1 on each axle. The outer CV joint connects the axle shaft to the wheel and experiences more movement. In fact, the CV joints are only as good as the boot. The most common symptoms of a failed CV joint include clicking and popping noises while turning or when accelerating.
CV joint: Oftentimes, CV joints wear out half of the axle shaft. While repairing a CV joint is a viable repair, it is more expensive than replacing the axle. In most cases, you should replace the CV joint. Replacement will save you time and money. ACV joints are a vital part of your vehicle’s drivetrain. Even if they are worn, they should be checked if they are loose.
Unresponsive acceleration: The vehicle may be jerky, shuddering, or slipping. This could be caused by a bent axle. The problem may be a loose U-joint or center bearing, and you should have your vehicle inspected immediately by a qualified mechanic. If you notice jerkiness, have a mechanic check the CV joints and other components of the vehicle. If these components are not working properly, the vehicle may be dangerous.
Driveshaft

Maintenance

There are several points of concern regarding the maintenance of axle shafts. It is imperative to check the axle for any damage and to lubricate it. If it is clean, it may be lubricated and is working properly. If not, it will require replacement. The CV boots need to be replaced. A broken axle shaft can result in catastrophic damage to the transmission or even cause an accident. Fortunately, there are several simple ways to maintain the axle shaft.
In addition to oil changes, it is important to check the differential lube level. Some differentials need cleaning or repacking every so often. CZPT Moreno Valley, CA technicians know how to inspect and maintain axles, and they can help you determine if a problem is affecting your vehicle’s performance. Some common signs of axle problems include excessive vibrations, clunking, and a high-pitched howling noise.
If you’ve noticed any of these warning signs, contact your vehicle’s manufacturer. Most manufacturers offer service for their axles. If it’s too rusted or damaged, they’ll replace it for you for free. If you’re in doubt, you can take it to a service center for a repair. They’ll be happy to assist you in any aspect of your vehicle’s maintenance. It’s never too early to begin.
CZPT Moreno Valley, CA technicians are well-versed in the repair of axles and differentials. The CV joint, which connects the car’s transmission to the rear wheels, is responsible for transferring the power from the engine to the wheels. Aside from the CV joint, there are also protective boots on both ends of the axle shaft. The protective boots can tear with age or use. When they tear, they allow grease and debris to escape and get into the joint.
While the CV joint is the most obvious place to replace it, this isn’t a time to ignore this important component. Taking care of the CV joint will protect your car from costly breakdowns at the track. While servicing half shafts can help prevent costly replacement of CV joints, it’s best to do it once a season or halfway through the season. ACV joints are essential for your car’s safety and function.

China Best Sales CZPT 6X6 All Wheel Drive Tractor Truck Head Low Price for Sale   with Free Design CustomChina Best Sales CZPT 6X6 All Wheel Drive Tractor Truck Head Low Price for Sale   with Free Design Custom