1.Request for Quote from CAD Drawing
YES, I already have CAD drawing - send us RFQ.

NO, I don’t have CAD drawing
Make Your Own CAD Drawing
Reverse Engineering: From Real Component to Print

 

2.Project Reviewing
Part Specifications for Quote

3.Quotation
Quote Details You Must Know

4.Let's Move to Production
Order & Proforma Invoice
Payment Terms

5.Quality Control
Inspection Procedures
QC Reports
Delivery
Packaging
Shipping Arrangement

6.Industrial Applications
Analytical Chemistry
Auto parts
Camera Components
Hose Fittings
Lighting Application
Medical Supply
Robot

7.CNC Machining Services
CNC Milling Machining Parts
CNC Lathe Machining Parts
Machinery & Equipment：CNC Machining Machinery

8.What is CNC machining?
Computer numerical control(CNC) could be a powerful machine which fixed and rotated the raw material rod on it’s driving headstock, to remove the material by means of relative movement between various cutting tools and raw material rod. Advanced programming software which optimized machine setting, cutting time, surface finish, and fine turning tolerance is used to control a CNC turning milling machine according to the instructions of clients’ CAD drawing file.

Our CNC production lines are not only to manufacture turning part workpieces and prototypes, but also to build molding tools, which are to be used for plastic injection molding or die casting.

 

9.Types of CNC Production Lines
we offer our clients with varies of CNC services including turning, milling, drilling, grinding and much more. Our engineer can use precision manufacturing production lines such as 3, 4 and 5 axis machine centers to make parts base on clients’ 2D and 3D CAD drawings. CNC Hobbing is mainly used for cutting gears, splines, and key slots. CNC plasma cutters and CNC water jet cutters are used for profile cutting of the sheet material.

No matter your are looking for precision plastics, aluminum, stainless steel parts manufacturing, our production lines are capable of wide range of precision parts made of plastics or metals. Contact our team to get a free quote and to discuss which manufacturing process is the most efficient and suitable one for your project.

10.From CAD drawing to machined parts
We are capable of making parts from the print via CAM software, CNC turning and milling machines.

1.) Checking and confirming your CAD drawings

Once order confirmed, 2D and 3D CAD drawings well received from clients. Till today, more than ten thouthand CAD drawings been checked and confirmed before production to feedback if there are any problems opening the drawing files or other obvious issues:

a.) To receive a “no quote” if the part is outside HEHUA’s capabilities.

b.) To receive suggestions for ways to improve design for production, also to reduce cost without losing functionality.

c.) To receive a quote with the shortest possible lead time for delivery.  

2.) Programming

Our professional CNC programmers use PC-based CAD/CAM software Mastercam for fast and efficient turning/milling. During this stage, we keep looking for better way to optimize design for production.  

3.) Production

Following instruction of CAM software, step by step well manufactured via CNC milling machine centers while our production lines are capable of 2 axis, 3 axis, 4 axis and 5 axis CNC machines. From simple dowel pins, shaft to complex turning-milling parts, we have got you covered.  

 

11.CNC machining vs 3D Printing
3D printing is kind of parts manufacturing through additive methods, featured with:
Flexible Design
Rapid Prototyping
Print on Demand
Strong and Lightweight Parts
Fast Design and Production
Minimising Waste
Cost Effective
Ease of Access

Compare to 3D printing, parts manufactured via CNC machining services could be generally stronger and have much better production quality and finish. Eventually, CNC machining is typically used from early to late stages of project development whenever parts are ready to be sample tested for functional accuracy or mass production.

 

12.CNC Machining Material
Plastic
Alloy Steel, Carbon Steel
Aluminum Alloy
Brass, Bronze, Copper
Stainless Steel

 

13.Material for CNC Machining Service

Lots materials can be used create plenty of options to manufacture no matter you would like with the CNC machines. From metal to plastic or even from wood to wax, the material options are literally endless as far as what materials can be used and what people are designing. In summary, the major advantages of CNC machining service are various of materials that can be used with them for plenty of options.

 

14.Material Capability

Our CNC offers a wide variety of materials for your custom parts: aluminum, carbon steel, alloy steel, stainless steel, copper, brass, bronze, nylon, acetal, polycarbonate, polystyrene, acrylic, plastic, fiber glass and many more materials.

Materials can be supplied in rod, tube, sheet metal, bulk profiles for better production arrangement.

 

15.Tips of Choosing Material

It is challenge to decide on the best material for your CNC machined part. Generally speaking, there are various factors to make the decision. For instance, price, hardness, tolerance, environment, surface treatment, etc.

Below are some tips:
Metals allow cnc machining parts with better tolerance than plastics.
Plastics is lighter, but could deform slightly over time due to moisture absorption.
Parts made by sheet metal is generally lower cost than machining from plate or rod.
Materials that don’t need finishing may be more economical for fastest production (e.g. stainless steel, plastics, titanium, etc.)

16.Sheet Metal Fabrication Service
Fast, repeatable, and automated production on state-of-the art Amada laser & punch press cutting equipment. Our facility is optimized for medium to high volume manufacturing.

Service Highlights
State-of-the-Art Laser/Punch Press Technology
Automated Loaders for 24/7 Cutting Production
Cutting Capabilities up to 0.25″ Material Thickness
Accurate Ram Systems Designed for Repeatability
Forming Capabilities up to 10 Feet in Length
2D & 3D Scanning for Quality Assurance

17.About Sheet Metal Fabrication

Sheet metal fabrication typically begins by cutting flat stock sheet metal to specification. First batch parts are quality checked by trained team members on Fabrivision imaging systems to verify parts are good and meet requirements.

Once cut, parts are broken out from the sheet, then referred to as a skeleton, and moved onto the next process.

Sheet metal is bent, or formed, from two dimensions to three by the use of hardened steel tools and dies which, when forced together with hydraulic power, form the sheet metal to shape and exact angle.

18.Stamping molds: the process in detail

The mold is a matrix which is specifically designed as a tool in some industrial manufacturing processes such as molding, casting, deep drawing, foaming or sintering: serves to give the final or intermediate form to the workpiece or the material to be processed.

In precision metal stamping, a mold is usually composed of two or more half-shells, ranging to delimit an area of the space with the shape of the piece to be obtained. The stamping of a mold is usually made of hardened steel (a thermal process to improve its characteristics), or tempered.

Molds of less resistant materials, such as chalk, or silicone resin are used for the production of small series for rapid prototyping. The useful life of a mold can go from a few pieces, or even just one, to thousands of millions of copies.

19.The stamping mold processes

Stamping mold is the process of making pressure on the blank so that the blank will undergo steel transformation or separation to produce workpieces with fixed sizes, shapes and properties.

The molds are made according to the processes of traditional milling or high speed, to reach the shape are used for 7-axis milling machines. The active parts of the mold are also used as electrical discharge machines (wire or tuff), lathes, and grinders.

In the precision metal stamping field, the mold must usually be designed without cavities that might restrict the removal of the piece: in particular, undercuts are to be avoided, that is, angles of 90° or more, which in fact make the printed indivisible element from the mold.

The stamp of a mold must pay particular attention to the draft angles: since the creation of the walls perfectly in axis with the extraction movement could give problems in the removal of the finished parts, the walls should never be designed vertical but must have a slight angle (1 or 2 degrees) to the outside. To exemplify, a cylinder should be converted into a truncated cone in order to be extracted without problems.

In the molding of sheet metal, the mold is made from a steel block, divided into two parts, one on the base and the other on the movable part of the machine tool, which deforms the material to obtain even with subsequent steps (and with molds gradually slightly different) the final shape of the piece industrial.

A process of precision mold stamping is known as deep drawing. It is a very difficult task, which must be divided into several steps to prevent the sheets from being stretched excessively and therefore can tear or bring thinning non-uniform.

20.Different types of stamping molds

According to the different stamping molds, these last can be divided into five categories: punching and shearing molds, bending molds, drawing molds, forming molds and compression molds.

Punching and shearing dies. Commonly used shapes are shearing molds, punching molds, trimming molds and edge molds.

Bending mold. It consists of bending the flat blank at an angle. Depending on the shape, precision and production volume of the part, there are many different forms of mold, such as ordinary bending mold, cam bending mold, curling mold, arc bending mold, punching bending mold, twisting mold and so on.

Drawing dies. Drawing mold allows you to make a flat vacuum in a container seamlessly with the bottom.

Forming mold. This refers to the use of various methods of forming the mold. It can be convex, curled, neck, and round edge hole flange.

Compression mold. Uses strong pressure to flow and deform raw metal into the required shape. Its types include extrusion mold, embossing mold, and final pressure mold.

21.Why choose us for stamping molds

We puts at the center of its business the attention to the customer, designing and manufacturing customized molds. This is a very delicate process as the mold must fit perfectly for the purpose for which it will be used. So the process of designing and building a mold must be precise and carried out by qualified personnel, from engineers to operators.

If you need a mold, get in touch with one of our experts.Contact us!

International Standards
Metric External Thread Chart
General Tolerances ISO 2768-1/JIS B 0405
Tolerances for holes(ISO 2862)
Hardness on workpiece?
Surface Roughness Table
NPS/NPT
BSPP(G) BSPT(R)
Knurling(DIN 82)
Plating Specifications
PG screw thread

 

Metric External Thread Chart

Metric threads, no matter the external one or inner one, are widely used on the CNC machined parts. Threads can take an important role for assembly, mating and functional adjustment. Our CNC machining services could provide you the parts with precise manufactured thread which is inspected with thread gauge to ensure the quality.

 

General Note: All dimensions are in millimeters.

 

General Tolerances ISO 2768-1/JIS B 0405

CNC machining and Sheet metal fabrication service, shanghai based factory in line with international standard, such as general tolerance ISO 2768 ISO9001 or JIS B 0405. Please refer to the ISO 2768/JIS B 0405 tables below in details.

 

Table 1 – Linear Dimensions

* For nominal size below 0.5mm, the deviation shall be indicated adjacent to the relevant nominal size(s).

Table 2 – External Radii and Chamfer Heights

Table 3 – Angular Dimensions

General Tolerances ISO 9001/IATF16949 /EN15085

GENERAL TOLERANCES FOR FORM AND POSITION

There are several common requirements for CNC machining services, such like straightness, flatness, perpendicularity, symmetry, run-out, and etc. A machined part may distort, tilt due to various situations:
Raw material stiffness
Raw material internal stress
Poor machining process

The CNC machine is out of alignment
Therefore, we will have to inspect the machined parts based on ISO 2768-2/JIS B 0419 below.

Table 1 – Straightness and Flatness

Table 2 – Perpendicularity

Table 3 – Symmetry

Table 4 – Run Out

 

Tolerances for holes(ISO 2862)

The importance of holes on a cnc machined parts is no less than the threads. Parts are usually made to assemble with other ones. When it talks about assembly, the standards tolerances below takes important roles on it. In other words, the relationship between the two mating parts could be determined by “fitting”. Generally speaking, there are three kinds of fitting below:

 

 transition fitting

A transition fitting is known as a slip or push fit for the mating parts. This kind of fitting is usually required a highly accurate alignment or tolerance between the mating parts. Under a transition fitting, the mating parts could perform a fitting without excess play or movement in the assembly.

 interference fitting

An interference fitting is so called press fit, tight fit or friction fit. It is usually used in fixing the bearing on to a shaft or a hole, a dowel pin into a hole. It may sometimes use to assembly spare parts into a single unit to reduce the raw material and production cost.

Besides, considering an optimize performance on fixing the bearing into the hole, the hole finished with burnishing process could provide a firm and consistence surface quality. You could refer to Sandy Munro’s comments on the motor of Tesla Model S Plaid at 8’28”.

slide fitting

The slide fitting is so called clearance fit or loose mating. The mating parts with a slide fitting could slide in and out without any restriction. A grinding process would be helpful to optimize the surface quality on the mating parts to slide freely between each other.

Hardness on workpiece?

The required hardness of a workpiece could be defined by its functionality. If a harder or softer hardness on the workpiece is required, heat treatment will be helpful for modifying it specification. Typically, we are using some kinds of differnt heat treatment below to meet the requirements:

1.) quenching

The way to increase the hardness of workpiece made of carbon steel or alloy steel is general performed by quenching which is to heat the workpiece above its critical temperature and hold for a period of time. After that, the workpiece have to be rapidly cooling in the water, oil or air to complete the quenching process. In that way, quenching could increase the hardness but decrease the ductile of the workpiece.

2.) tempering

Tempering is used to increase the toughness of the tooling or spring made of carbon steel or alloy steel. For parts featuring with excess hardness or becoming too hard/brittle after quenching, a consequently tempering process could reduce the hardness and increase the ductile by heating the workpiece to a temperature below its critical point and then steadily cooling to a lower termperature

3.) anealing

Anealing is similar to tempering which is also capable of altering the properties of a workpiece to reduce its hardness and increase its ductile. Under a proper heating temperature, the freedom moving atoms of the metal workpiece could achieve a more equilibrium state. After the heating stage, the workpiece is usually left in the oven for steadily cooling while recrystallization and grain growth are happening. For parts made of carbon steel or alloy steel, if it is a terminal or connector spare part for crimping, a anealing heat treatment might be required.

4.) case hardening

There are a lots of heat treatment methods to partially harden the workpiece. Case hardening is capable of increasing the stiffness of the outer case of a carbon steel of alloy steel, and keep its core area soft as before for better ductile property. The hardened outer case of the workpiece can be much more durable and wear resistant. However, the hardened surface will be no longer suitable for machining. Therefore, case hardening is generally applied once the workpiece has been completed from CNC machining process.

Tensile Strength Rm 820-2180 [MPa]

Vickers: F ≥ 98 N, diamond pyramid (HV)

Brinell: F = 29.421 N, ball ø 10 mm (HB)

Rockwell: F = 1,471 N, diamond cone (HRC)

 

Tensile Strength Rm 255-930 [MPa]

1 MPa = 1 N/mm²

 

Vickers: F ≥ 98 N, diamond pyramid (HV)

Brinell: F = 29.421 N, ball ø 10 mm (HB)

Rockwell: F = 980 N, ball 1/16″ (HRB)

 

Surface Roughness Table

Surface roughness Ra is a measurement of the deviation of a surface from a mean height. The lower Ra measurement, the higher grade surface quality. At the same time, the more machining process will be required. Generally speaking, a workpiece completed by CNC lathe or milling could reach a surface roughness between Ra 0.8-3.2.

 

Based on the capability of our CNC machining service, we are capable of manufacturing aluminum alloy parts with suface roughness between Ra 0.1-0.2 where is required on an ABS system for optimized piston movement. Normally, we supply the machined parts within Ra0.8-3.2. For your reference, the higher grade surface roughness, the more expensive production cost.

* micro-meters(um) = 0.001mm

** micro-inches(u”) = 0.0254um

NPS/NPT

National Pipe Straight thread (NPS)

Both NPT and NPS have the same thread angle 60° included angle and have flat peaks and valleys, and pitch (TPI, thread per inch). However, NPT threads are tapered and NPS threads are straight (parallel). Be noticed that NPS need a gasket or O-ring to create a seal.

National Pipe Taper thread (NPT)

American National Standard Taper Pipe Thread (*Ref), often called NPT for short. The taper on NPT threads allows them to form a seal when torqued as the flanks of the threads compress against each other. In other words, threaded pipes are able to provide an effective seal for pipes transporting liquids, gases, steam, and hydraulic fluid.

BSPP(G) / BSPT(R)

British Standard Pipe Taper thread (R)

Taper threads, British Standard Pipe Taper thread (BSPT), whose diameter increases or decreases along the length of the thread; denoted by the letter R. The taper is 1:16, meaning that for each 16 units of measurement increase in the distance from the end, the diameter increases by 1 unit of measurement.

  The thread form follows the British Standard Whitworth standard:

1.) Symmetrical V-thread in which the angle between the flanks is 55° (measured in an axial plane)

2.) One-sixth of this sharp V is truncated at the top and the bottom

3.) The threads are rounded equally at crests and roots by circular arcs ending tangentially with the flanks where r ≈ 0.1373P

4.) The theoretical depth of the thread is therefore 0.6403 times the nominal pitch h ≈ 0.6403P

British Standard Pipe thread (G)

British Standard Pipe Parallel thread (BSPP, originally also known as British Standard Pipe Fitting thread/BSPF and British Standard Pipe Mechanical thread/BSPM), which have a constant diameter; denoted by the letter G (*Ref).

The thread form follows the British Standard Whitworth standard:

1.) Symmetrical V-thread in which the angle between the flanks is 55° (measured in an axial plane)

2.) One-sixth of this sharp V is truncated at the top and the bottom

3.) The threads are rounded equally at crests and roots by circular arcs ending tangentially with the flanks where r ≈ 0.1373P

4.) The theoretical depth of the thread is therefore 0.6403 times the nominal pitch h ≈ 0.6403P

Knurling(DIN 82)

DIN 82 Knurling, standard by Deutsches Institut Fur Normung E.V. (German National Standard), published on Jan. 01, 1973.

There are generally two different types of knurling process: cut knurling and form knurling. Each of these processes has its own particular areas of application with correlated properties:

Ref: How to control the tolerance after knurling?

Form knurling

• The external diameter of the workpiece will be increased.

• It will compress the surface of the workpiece.

• Not recommended for thin materials.

• Form knurling on workpieces with a small diameter is possible to result in slightly plastic deformation on its end, as mentioned previously in “Diamond Knurling Operation on CNC Lathe”.

• The CNC lathe is subjected to a greater load due to the higher pressure.

• Slower cutting speed and feed rate, compared to cutting knurling.

Cut knurling

• Maximum precision and surface quality

• Can be used for knurling thin materials without deformation

• Saves time on account of higher cutting speed and feed rate

• Compatible with virtually any material, including cast iron and plastic

• Cutting process with less loading protects the top end CNC lathe.

• No or minimal changes to the external workpiece diameter.

 

Plating Specifications

Alodine / Chemical Conversion

Alodine, so called chromatic passivation or chemical film for aluminum is a chemical conversion process under the MIL-DTL-5541 specification. These coating processes are categorized by the following types, classes and colors.

Anodizing

The most common acids used for aluminum anodizing are sulfuric or chromic. U.S. Mil-A-8625 is also the most commonly referenced specification, and describes 3 general types of anodizing:

Zinc Plating

Zinc plating is the process of covering substrate metals (like carbon steel and alloy steel, etc.) with a layer of zinc to protect the substrate from corrosion. It is usually used to protect and improve the appearance of ferrous metals, as a corrosion barrier. Our Zinc Plating is basically according to ASTM B-633 ELECTRODEPOSITED COATINGS OF ZINC ON IRON AND STEEL.

ASTM Type

PG screw thread

The Panzergewinde screw thread, more often called by the shorter name PG screw thread, was a technical standard created in Germany. The standard, codified by the Deutsches Institut für Normung (DIN, German Institute for Standardization), is DIN 40430. Panzergewinde sizes are named with the prefix PG plus a nominal number which approximately corresponds to the maximum cable diameter (in millimeters) that can be passed through the conduit. Because the walls of the conduit are usually relatively thin, the thread depth is limited. Thus a thread angle of 80° is used

*Ref.: Learn more about

Quality Control Process

Nothing is more important than production quality. As a professional CNC machining manufacturer, we have set up a critical SOP of quality control process as below. Generally speaking, we define four steps of quality inspection proess for each production. The inspection items is usually including incoming raw material, machioning process, finished CNC machining parts.

IQC (Incoming Quality Control)

All incoming raw material for CNC machining production are checked and marked for receipt inspection before used. Varies measurements are taken to check against approved data. Once rejected, raw material are sent back for further examination.

Quality Control Process

We perform inspections during the CNC machining maufacturing process. Frequency of inspection depends on the quality standard set forth by the project. All manufacture datas are recorded for future reference.

FQC (Final Quality Control)

All finished CNC machined parts are inspected according to our quality standard for each project. Products are sampled according to the AQL sampling rate before they leave our production plant into the warehouse.

OQC (Out-going Quality Control)

Our QC team will randomly check any finished goods in the warehouse before it goes out for shipment. This last inspection ensure zero defect goods are shipped to our customer.