Factory Directly High Quality Chinese Manufacture Welded Tube Hydraulic Cylinder

All sizes are avaliable for choosing

About Us
Established in 1988, Ningbo LD Machinery Co, LTD. (hereinafter referred to "LD") is a leading manufacturer specializing in the design, research, development, manufacture and marketing in the hydraulic industry. Being one of major suppliers of customized components and cylinders for manufacturers spreaded all over the world, the company is committed to offer high quality products with competitive prices and excellent service worldwide.

Headquartered in Ningbo City, Zhejiang Province, the company wholly owns a subsidiary production factory named "Ningbo YUEWEI Hydraulic Technology Co., Ltd", which covers an area of more than 380,000 square meters, possesses abundant technical strength and sound production management system, superior machining production equipment, strict and effective quality control system, advanced and excellent inspection instruments.

More than 35 years experience in machining industry, with over 10 experienced technical engineers and 150 skilled workers, LD has a senior engineering technical team with special skills and rich experience in product design, casting, forging, and CNC machining, can handle special material, structure, defect and processing, meet the evolving needs, and provide optimal solution and real one-stop service to customers.
 

Hydraulic Cylinder Producing Process

Step1: Quality Control on Raw Material
We have our own lab in factory, inspect the raw material and do the test. For every batch of material we received, we will ask supplier provide their certificate, and then cut them to do the test again to see if the results match the certification. Also, every batch we received, we will cut them into pieces to check the air bubbles. Once they are all qualified, we will accept it, and all detail information will be recording in our ERP system. We will also pay lot of attention on the salt spray test for chrome rod. Every month, we will cut the material, put them into test machine to see if it reach the requirement. All the result will be recorded at our QC department. If customer need, we can provide it.

Step2: Quality Control on Machining
we start doing components machining from 1988 with 36 years experience now and insist doing 100% inspection. We spend lots of money, invest on auto robots and machines. Now half of the producing line is by robot so that we can ensure our quality be stable good. For every part of the cylinder, we do 3 times inspecting. Firstly, workers will do self inspection. Secondly, we have tour-hour inspection checking the products, two times in the morning and two times in the afternoon, make sure that every step is good. After the products are all completed, we will do 100% inspection. For thread, for the tolerance, everything, we need double check. Also, we have specific warehouse just for the measuring tools. Every inspector have their own measuring tool and we will check the measuring tools regularly to make sure they are all in good condition, so that the measuring results will be convincing.

Step3: Quality Control on Welding
We are qualified to AWS certification, which is very popular in North American market. First, for the visual test, we will make sure that every components are welded good, look beautiful. And the second, we need to check the penetration. We have more than 15 years experience, we do know what kind of designing angle can make the cylinder welding strong. Once we finish the first article, we will cut it and analyse the welding to see if it is fulfill the groove. And then do the radiographic testing to make sure there is no gap inside. What's more, we will do the ultrasonic test to check the program for the robot. Now 80% of welding is doing by robot. Once the program confirmed, no one can change it unless the welding manager, and they only have 5% right.

Step4: Quality Control on Assembling
For assembling, we have some difference with others. The brand we uses for seals are all those famous brand like Aston, Parker, Hallite. The cylinder we give to our customer has two years warranty. For our company, we engrave our part number and manufacturing date for the quality warranty. So no matter for seals or any others, as long as they are parts of cylinder, if it is under two years, we will take responsibility for them. And we will do the test for every cylinder like for pressure after we finish assembling.

Step5: Quality Control on Painting
We have our half auto painting line. Right now, we can paint about 1500 cylinders per day, which is about one container. Before we do the painting, we will do the wash first and for every cylinder, we will test for hardness, thickness and adhesion to make sure the painting are all good, which will be recorded into OQC report, print out and stick on the box, ship to you with your products.

Step6: Hydraulic Cylinder Packing
For every cylinder, we have the stick to show the detail information like bore size, stroke and working pressure. And we will use individual plastic bag packing. If customer need, we can also use individual carton box packing. We will fasten one floor after one floor with plat, so customer can only cut what they need and other layer will still be fasten. Moreover, there will be plywood pallet or plywood box for customer choosing. We will also send the loading picture to customer after we ship them to make sure everything is well loaded in China.

Packing Reference

Order Process

Enterprise Features

FAQ
Q1. What is LD product's quality assurance?
100% inspection for each product before shipping with inspection rereport for tracking.

Q2: How long is the warranty on LD products?
The warranty is 2 years for general products since the date of shipment.

Q3: How LD deal with the quality problem during warranty period?
1. LD will take the corresponding cost caused by customer local reparing. 
2. LD will provide the product by free if the repair cost is higher than the product value, but the freight involved shall be borne by customer side.

Q4: How to ensure the order can be shipped on time?
LD will send the "production schedule" every week after receiving customers' orders. If any delays, LD will inform customers 3 weeks in advance, so as to facilitate the customer to arrange the schedule.

Q5: Does LD offer delivery service?
Yes. LD has deep cooperation with logistics companies all over the world to provide customers with quick and convenient "Door-to-Door services",including sea, air and express.

Q6: How LD control the product quality?
1. Raw materials: We will test the material of each batch of raw materials we receive, and the piston rod will be tested with salt spray. This is to ensure that the material of our products meets the requirements at the beginning.
2. Processing: We have the leading machining equipment, and obtained ISO9001 certification.
3. Welding: Our factory is equipped with welding robots, and has obtained the AWS certification.
4. Assembly pressure test: 100% testing with OQC report for chaining. The seals we use are: Hallite, Aston and Gapi