COMSCO — Yangzhou Com Spare Industry Co., Ltd. — is a tube mill manufacturer in Yangzhou, Jiangsu, China, working since 2016. We build ERW tube mill lines from HG16 to HG355, and we make the parts that decide how a line performs: the roll tooling, the seam welding equipment and the flying cold saw.
How We Work
- Module by module: each critical module is built in our own workshop.
- Lines configured to your tube, wall and line speed, not sold from a list.
- 150+ mills and cut-off lines running in more than 15 countries.
- Spare parts, blades and impeder cores shipped after the sale as well.
Most of our customers are in Southeast Asia, the Middle East, Africa and South America. Send your tube specification and you will have a proposal, with the stations priced separately, within two working days.
What “Manufacturer” Should Mean
There are hundreds of companies that will sell you a tube mill. Far fewer can tell you the hardness of the roll they just made, where the ferrite in your impeder came from, or which of their own machines is running in a plant you can telephone. The difference between a manufacturer and an assembler is not the size of the catalogue. It is whether the parts that decide quality are made under the same roof.
On an ERW line, three things decide whether the tube is saleable: the roll tooling, the weld, and the cut end. Everything else is structure, drives and handling. A supplier who makes those three has control over the machine. A supplier who buys them has a supply chain, and when something goes wrong the answer becomes a shipment date instead of a solution.
A Twelve-Point Factory Walk-Through
- Are the roll drawings in the same building as the lathes, or does the drawing travel by email?
- Is there a heat treatment furnace on site, and can you see a hardness test report for the last set?
- Are the rolls finished ground after hardening, or only turned?
- Is the welder assembled and tested on site, or delivered in a crate?
- Can you watch a saw being run in on a test piece before it is packed?
- What test equipment exists for the finished machine — laser alignment, hardness tester, gauge sets?
- How many machines are in build, and how many people are on the floor?
- Is there a spare parts store, and can you photograph the shelf?
- Which parts are subcontracted, and who supplies the HF boards and the ferrite?
- Is there a written commissioning procedure, or does the fitter improvise?
- What documentation is produced, and in which language?
- Can you meet the person who will answer the telephone in two years?
References You Can Actually Use
A reference list of countries is marketing. A reference you can call is evidence. Ask for two customers running the same model on the same kind of product, in a time zone you can telephone during their shift, and ask them three questions: does the mill hold size, how long did commissioning take, and when a part broke, how long did the replacement take to arrive.
We are happy to be asked that, and we will give you the customer’s own words rather than a logo. Our machines run in more than fifteen countries; the ones worth talking about are the ones where the buyer will take your call.
Documentation That Should Arrive With the Machine
- General arrangement drawing and foundation plan.
- Electrical schematic and a backup of the PLC program.
- Hydraulic and pneumatic diagrams with component part numbers.
- Roll drawings for every pass, with the tube size they were cut for.
- Setup sheet: pass line height, roll gaps, weld settings, saw parameters.
- Spare parts list with part numbers and lead times.
- Operation and maintenance manual in the language of the operators.
- Material and hardness certificates for the rolls.
- Factory acceptance test report with the measured values.
A machine that arrives without the PLC backup is a machine you cannot troubleshoot. That is not a paperwork complaint — it is a downtime risk with a date on it.
Factory Acceptance Test: What to Watch
A FAT that consists of running the mill empty proves the motors turn. Run a coil. Then measure: OD at four points on ten tubes, wall at four points, ovality, cut length on twenty consecutive pieces, squareness of the cut, burr height, and a flattening test on the weld. Record the line speed at which those numbers were achieved. If the supplier will not run a coil before shipment, the commissioning becomes the acceptance test, in your plant, on your schedule, with your customer waiting.
Shipping, Erection and the First Coil
A container leaves the factory and the project stops being about machines and starts being about logistics: packing that survives two transfers, a packing list that matches what arrives, foundation work done before the crate lands, a crane booked for the right week, and an engineer with a visa. Ask for the erection scope in writing — days on site, who pays travel, who supplies the crane and the consumables, and what happens if the foundation is not ready.
Warranty, Spares and the Machine After This One
Warranty terms matter less than the answer to one question: when a part fails in year three, who makes it? If the answer is “we will check with our supplier”, the part is now on someone else’s schedule. Because the roll tooling, the welder assembly and the saw are built in our workshops, the answer here is a drawing number and a lead time.
That is also the reason a second machine usually comes from the same supplier: the roll sets interchange, the setup sheets are the same, and the operators already know where the controls are.
From the Knowledge Centre
- Specifying a Tube Mill Line: Ten Numbers for the First Meeting
- Accumulator Sizing: What a Coil Change Really Costs
Related Products
Looking for something close to this? ERW tube mill line · Roll tooling · Flying cold saw · Spare parts.
