Furnaces

Industrial Melting Furnace Manufacturer: The Complete OPDEL Furnace Range

OPDEL designs and supplies industrial melting furnaces and heat treatment furnaces for jewellery manufacturers, gold and silver refiners, bullion producers and precious-metal casting houses. The range runs from 1 kg desktop induction melters through 40 kg tilting furnaces to modular industrial systems rated for 20–900 kg of steel or 40–1300 kg of brass, alongside annealing, tunnel, burnout and continuous casting furnaces. This page is the entry point to the full range; each model family below links to its own specification page.

The four furnace families

OPDEL furnaces divide into four groups by what they are asked to do. Buyers usually need one or two of them, not all four.

Induction melting furnaces turn solid charge into a controlled, homogeneous melt. Induction heats the metal itself rather than a chamber around it, so cycles are short and the melt is stirred electromagnetically as it forms. These are the OPEMelt, OPUMelt and OPUM ITC lines.

Heat treatment furnaces work on solid metal after casting: annealing chain and sheet, tempering, stress relieving, and burning out investment flasks. See the heat treatment furnace range.

Continuous casting furnaces melt and solidify in one uninterrupted operation, pulling wire, flat bar or tube out of a water-cooled die instead of pouring ingot. See Vulcano and Etna.

Vacuum and pressure casting furnaces melt under argon protection and fill flasks by vacuum with gas pressure, for lost-wax work. See the F1000 and F2000 casting machines and the vacuum chamber units.

Induction melting: static or tilting

The first decision is whether the crucible stays put or pours.

In a static furnace the crucible is fixed and the operator pours by lifting it out or by tapping. The design is compact, stable and simple to maintain, which suits small and medium production and controlled melting where the crucible is not moved every cycle. There is more on this in the static induction furnace overview for gold and silver.

In a tilting furnace the furnace body rotates to pour. Above roughly 10 kg of gold, manual crucible handling stops being practical, so tilting becomes the safety and ergonomics answer rather than a luxury. The OPUMelt TLT tilting station is a compact bench solution that pairs with a Solo 12 or Solo 16 generator; the OPUmelt TF is a floor-standing heavy-duty unit with automatic tilting control for up to 40 kg of gold or 25 kg of silver.

Concrete capabilities across the melting range

All induction melting units in the table use external water cooling. The desktop OPEM units need a minimum of 0.8 LpM; the OPUM 4/5 units need 2.0 LpM. Both accept inlet water up to a maximum of 35 °C, which in most Indian and Gulf installations means a chiller rather than mains water.

Features that matter on the shop floor

• Power regulation from 10% to 100% with a bar-graph indicator on the OPEM, OPUM and OPUmelt TF units, so a small charge can be brought up gently instead of being shocked at full power.
• Temperature control by K-type thermocouple probe, or optional IR pyrometer, which is the practical way to stop overheating and burning of gold above its liquidus.
• Digital control with built-in diagnostics on the OPUM and OPUmelt lines, which shortens fault-finding when a unit stops mid-shift.
• RS485 communication on the OPUmelt TF for integration with production monitoring systems.
• Automatic tilting control on the OPUmelt TF for repeatable pour rate, the variable that most affects bar surface on manual pours.
• Stainless steel front panels and high-temperature top covers across the OPEM and OPUM range.
• Fume collection ring and hoist or hydraulic tilting on the OPUM ITC for heavy industrial duty.

What this buys a capital-equipment buyer

Induction melting is chosen over resistance and flame melting for four measurable reasons. Metal loss falls because heating time in the oxidising window is short and the melt can be run under gas protection. Cycle time falls because energy goes into the charge directly, not into a hot chamber. Consistency improves because the same power profile and the same measured temperature produce the same melt every time, which is what a refiner needs to hold assay and a jewellery house needs to hold alloy colour. Running cost falls because the furnace draws power only when melting.

Against that, the honest counterweights are the water-cooling requirement, the three-phase supply needed above 5 kW, and crucible consumption. Budget for all three at the quotation stage rather than after commissioning.

Heat treatment and finishing furnaces

Melting is only the first thermal step. The FR annealing series uses a tubular frame with louvred panels, refractory-insulated muffles and stainless steel heating chambers, with nozzles admitting protective gas and a front burner to exclude oxygen and improve de-oxidation. Annealed material is pushed through to a cooling chamber and quenched in a water tub, recovered manually or by pneumatic piston. The series spans models aD 010 to aD 050 with increasing power ratings and chamber sizes.

The FN series uses two heating chambers with independently set temperature zones and a water-cooled cooling chamber, with burners at both tunnel ends. Models bD 020 to bD 050 run at 3 × 400 V, with 3 × 230 V optional, to a maximum of 950 °C, or 1100 °C as an option. On both series, ammonia, nitrogen and hydrogen pressure regulators and an NH3 dissociator are available as options.

The FRC series is a range of muffle electric furnaces for preparing casting cylinders, adjustable up to 850 °C for wax burnout and plaster firing, with a grill and drawer in the chamber base to recover wax.

Continuous casting and lost-wax furnaces

For plants making wire, plate or tube rather than ingot, the Vulcano cD series covers reduced crucible capacities, with cD 3 and cD 5 as bench units and cD 7 and cD 12 as floor-standing machines, operating to 1250 °C as standard and 1400 °C optionally on selected models, casting from 3.6 kg of 18 kt gold to 12.7 kg of 24 kt gold and up to 6.9 kg of 925 silver. The Etna cD series covers crucible capacities from 10 up to 140 kg for higher-volume special profile work.

For lost-wax casting, the OPC F1000 and F2000 melt small charges — 1.5 to 2.3 kg of 18 kt gold, 1.0 to 1.6 kg of 925 silver, 1.9 to 2.8 kg of 24 kt gold — at 4.5 and 5.0 kW respectively, to 1150 °C, casting by vacuum with gas pressure under argon protection.

Who uses these furnaces

Jewellery manufacturers, gold and silver refiners, bullion and minting operations, metal recyclers, casting workshops, research laboratories and industrial foundries. Metals covered across the range include gold, silver, platinum, copper, brass, bronze, other non-ferrous alloys and, on the U-suffix and ITC models, stainless steel.

Supporting equipment

Furnaces do not work alone. OPDEL also supplies induction power supplies from 5 kW to 35 kW, built around the modular Smart Power System with the Direct Digital Step control algorithm, and graphite crucibles and consumables for static furnaces, including extruded and isostatic crucibles, crucibles with fixed ceramic jackets, and graphite dies for plate, wire and tube production.

Frequently asked questions

How do I choose the right furnace capacity?

Size the furnace to your daily melt volume plus expected growth over the next three to five years, not to your peak day. An undersized furnace caps output; an oversized one raises both capital cost and running cost. Our furnace capacity selection guide covering 1 kg to 50 kg works through the arithmetic.

What electrical supply do I need?

It depends on the model. The desktop OPEM units and the OPUM 4/5 bench units run on single-phase 230 V ±10% at 50/60 Hz. The OPUM 12/16 units require three-phase 230/380–480 VAC, and the OPUmelt TF requires three-phase 380/480 V ±10%. An optional transformer is available on the OPUMelt 4/5 and 12/16 to support 3-phase / 230 V AC line requirements.

Do I need a water chiller?

Every induction melting unit in the range uses external water cooling with a maximum inlet water temperature of 35 °C. The OPEM desktop units need at least 0.8 LpM and the OPUM 4/5 units at least 2.0 LpM. Whether mains water can meet that continuously depends on your ambient conditions and duty cycle; most production installations use a closed-loop chiller.

What is included in installation and commissioning?

Which crucibles fit, and how long do they last?

Crucible capacity and volume are model-specific — for example, 280 cm³ on the OPUM 4G, 560 cm³ on the OPUM 5G, 1615 cm³ on the OPUmelt TF-20 and 3278 cm³ on the TF-40 — so crucibles are not interchangeable across models. OPDEL supplies matched graphite and ceramic-jacketed crucibles through its graphite consumables range. Crucible life depends on metal, temperature and cycle count.

Are spare parts and service available after purchase?

What is the lead time and the warranty?

Do the furnaces carry CE or other certification?

Request a quotation

Tell us the metal, the alloy, the batch size you melt per cycle, your daily volume and your available electrical supply, and we will recommend the model and capacity that fit. Reach us through the OPDEL contact page, or by phone or email to our Vadodara office in Gujarat, India. Quotations cover the furnace, the matched power supply where separate, crucibles, and any cooling or gas-protection equipment required to run it.

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