The cross beam end cap closes and clamps the tubular or box section cross beams that carry the deck frame on linear motion and high frequency vibrating screens. It sits directly in the load path between the exciter and the side plates, so any fretting, bolt loosening or crack at the cap brings the whole screen down. Ningbo Ruican casts the cap near net shape and machines the clamping bore, bolt faces and sealing surfaces, giving screen OEMs a fatigue-resistant structural casting that holds preload through millions of vibration cycles.
Specifications
| Parameter | Specification |
|---|---|
| Casting process | Silica sol lost wax investment casting; water glass process for heavier caps above 20 kg |
| Material options | Ductile iron EN-GJS-500-7 / 65-45-12; EN-GJS-600-3; AISI 1020; AISI 4140 / 42CrMo4; ASTM A352 LCC for low temperature duty |
| Dimensional tolerance (ISO 8062-3 CT grade) | CT7 as-cast standard; CT6 on request for caps under 150 mm across |
| Machining | CNC turning and 4-axis milling of the beam clamp bore, bolt pad faces and gasket seat; bore to H7 or H8 |
| Surface finish (Ra) | Ra 3.2 micrometres on machined clamping bore and bolt pads; Ra 6.3 as-cast; Ra 1.6 on gasket seats |
| Hardness / heat treatment | 170-230 HBW for ductile iron as-cast or normalized; 28-34 HRC for AISI 4140 quench and tempered; stress relieving standard |
| Weight range | 2.2 kg to 34 kg per end cap |
| Typical lead time | Tooling 4-6 weeks; first article samples 2-3 weeks after tooling approval; production 5-7 weeks |
Key features
- Near-net-shape casting reproduces internal stiffening ribs and the hollow beam socket, eliminating welded fabrications that crack under high frequency excitation.
- Clamping bore finish machined to H7 so the cap grips the cross beam evenly and prevents the micro-movement that causes fretting and bolt hole ovalisation.
- Radiused transitions between the socket, bolt pads and outer shell keep fatigue stress low at the points where fabricated caps normally fail first.
- Bolt pad faces machined flat within 0.05 mm so clamp load is shared across every fastener in the joint, protecting preload at 25-60 Hz screen frequencies.
- Stress relieving after rough machining removes residual casting stress, holding dimensional stability through the service life of the screen.
- Optional gasket seat machined to Ra 1.6, allowing the cap to double as a sealed closure for oil-lubricated or enclosed beam designs.
Applications
- Linear motion vibrating screens in aggregate, sand and quarry classification circuits.
- High frequency screens dewatering mineral slurries and fine sand products.
- Banana and multi-slope screens in coal preparation and iron ore plants.
- Flip-flow and banana screens handling difficult, sticky or wet material.
- Mobile and portable screening plants where deck frames see transport and site vibration.
- Recycling industry screens separating construction waste, compost and shredded fractions.
Images
Quality & compliance
Ningbo Ruican produces every cross beam end cap under an IATF 16949 certified process control system, documenting melt chemistry, nodularity for ductile iron grades, pouring parameters and heat treatment for each batch. Material certification to EN 10204 3.1 or ASTM equivalents accompanies every shipment, and heat treatment charts record the actual furnace trace including stress relief cycles. Hardness mapping across the socket wall, rib junctions and bolt pads confirms uniform mechanical properties, and tensile testing is performed on separately cast or integrally cast test bars from the same heat. CMM dimensional reports cover the clamping bore, bolt circle and gasket seat against the approved drawing, with FAI reports and PPAP Level 1 to Level 5 packages prepared on request. Magnetic particle inspection to ASTM E709 and dye penetrant inspection to ASTM E165 are available on all load path surfaces.
FAQ
Q1. Should the end cap be ductile iron or cast steel?
Ductile iron EN-GJS-500-7 covers most screen duty and damps vibration better than steel. We move to AISI 4140 quench and tempered when the screen runs at high stroke, carries heavy decks, or when the cap is part of a welded joint with steel side plates.
Q2. Can you match the bore to our existing cross beam dimensions?
Yes. Send the beam specification or a sample cap and we will machine the socket bore to your tolerance, whether the beam is round tube, square tube or a box section. We routinely hold H7 on the bore with concentricity inside 0.08 mm.
Q3. How do you manage fatigue at the rib junctions?
We specify minimum fillet radii in the tooling, avoid abrupt wall thickness changes, and shot peen fillet zones on request. For ductile iron grades we control nodularity above 90 percent. Every tooling design is reviewed for section transition before the die is cut.
Q4. Do you offer machining of the bolt holes as well?
We do. Bolt holes are drilled and spot faced in the same fixture setup as the clamping bore, so hole position relative to the beam axis stays within 0.15 mm and washers seat fully on machined pads. Holes can be supplied plain, threaded or reamed.
Q5. What surface protection can you supply?
Caps are shot blasted to Sa 2.5 as standard, then supplied primed, powder coated or painted to your colour and film thickness specification. We also supply bare machined parts with a rust preventative if you prefer to apply the final coating in your own facility.
Q6. Can you help redesign a fabricated cap as a casting?
Yes. Send the current weldment drawing and failure history and our engineers will propose a castable geometry with integrated ribs, improved fillets and fewer separate pieces. The result usually lowers piece count, shortens assembly time and removes the weld from the load path.
CTA
Share your cross beam end cap drawings, beam dimensions or a sample part and Ningbo Ruican will return a casting and machining proposal with material and fatigue recommendations, normally within three working days. Contact Wendy She at sales@cnsandcasting.com or on WhatsApp +86-13777124360, or visit cnsandcasting.com to begin.
