On May 18, Shenda Machinery handed off the DP9000-GJ2100 dual-stage extrusion injection press to Qingfa Piping in Foshan. It is a 9000-ton machine built for super-large PE100 pipe fittings, the kind used in large-bore water mains, drainage trunks, gas transmission lines, and the cooling loops of new nuclear plants. A single shot can weigh up to 1.55 tons.
The mold sitting on that press weighs 120 tons. KingHou’s job was to keep it locked, square, and changeable.
Why 32 clamps and not 16
A 120-ton mold cannot be held by four corner clamps. The opening force during injection of a 1.55-ton shot will pry the parting line if clamping is not distributed. We ran 32 self-propelled hydraulic clamps around the mold perimeter, each rated for the press platen pressure. Spacing is even on all four sides so the closing load is balanced across the mold face. There is no favored zone where the platen sees more force than the rest.
The other reason for going to 32 units is recovery. If one clamp throws a seal during a 24/7 production run, the remaining 31 can hold the mold safely while maintenance swaps the failed unit. With four corner clamps, one failure stops production.
Self-propelled is not a luxury
The Qingfa team changes molds about once every 10 days for product runs. A 120-ton mold takes a 90-ton bridge crane to lift, but you cannot hand-walk hydraulic clamps onto position once the mold is on the platen. There is no room, and the clamp itself weighs too much for two people.
Self-propelled means each clamp has its own drive and tracks. After the mold lands, the clamps drive themselves into position from the side of the platen, lock, and connect to the hydraulic line. Mold change drops from 6 to 8 hours of manual repositioning and bolting down to under 90 minutes.
One HPU, 32 clamps, one button
Pumping 32 individual cylinders up to identical pressure by hand is not realistic. We tied all 32 clamps to one super-large synchronous mold lock unit. The operator hits “lock” and all 32 close to the same set pressure within about two seconds. The HPU monitors pressure on every line and will refuse to fire the press cycle if any one clamp drops below target.
This is the part most pneumatic systems cannot match. Air clamps lose pressure as the mold cools and expand. On a 120-ton mold cycling between 230°C and 80°C through the day, that drift is enough to break a parting line.
What this means for large pipe fitting plants
Large pipe fittings are a brutal application for mold change. Molds are heavy, runs are long, and the press is too big to keep idle. Standard quick mold change kits built for 800 to 2000-ton injection machines do not scale to a 9000-ton press without reengineering the clamp count, the HPU sizing, and the control logic.
If your plant is moving above 5000 tons and your mold weights are crossing the 50-ton mark, the question is no longer whether you need hydraulic clamps. The question is how many, what spacing, what HPU flow, and whether the synchronous lock can hold the line under thermal cycling.
Project spec recap
Press: Shenda Machinery DP9000-GJ2100, 9000-ton clamping, dual-stage extrusion injection. Delivered to Qingfa Piping (Foshan) on May 18, 2026.
Mold: 120 tons, PE100 super-large pipe fittings, single-shot weight up to 1.55 tons.
KingHou configuration: 32 self-propelled hydraulic mold clamps, super-large synchronous mold lock unit, single HPU with per-line pressure feedback and automated lock-unlock sequencing.
Talk to engineering
Send us your machine tonnage and platen size. KINGHOU will recommend a suitable quick mold change solution.
Email: kh020@jskinghou.com | WhatsApp: +86 139 6188 6960
