CM-870 CNC Engraving and Milling Machine for High-Gloss Moulds

Engraving and milling machines sit between a machining centre and a jig grinder in purpose: light cuts, high spindle speeds and fine surface quality. The CM-870 from VITOP Machinery's CM series is the mid-size model, built for high-gloss mould finishing, copper electrode machining and small precision components such as watch parts. This guide explains the specification and where the machine fits.

Spindle Options and Speed Range

The spindle offers 500 to 18000 r/min and 24000 r/min configurations, driven by 8 or 11 kW depending on the option chosen. Output torque is 9 N.m, which tells you the machine is not designed for heavy hogging. Instead, small-diameter cutters run at speeds a BT40 machining centre cannot reach, producing fine finishes and crisp detail on ribs, textures and engraving. Tool holding is ER32 or BT30, and the installation diameter is Φ140 mm.

Key Specifications at a Glance

Structure and Accuracy

The machine uses a gantry-style layout with a 760 mm gantry width, which keeps the spindle supported on both sides and stiffens the Z axis for small tools. Positioning accuracy is ±0.003/300 mm and repeatability ±0.002/300 mm. On a high-gloss job, that repeatability is what lets you blend roughing and finishing passes without visible steps under polishing light.

Typical Applications

• Copper and graphite electrodes for EDM, machined with fine detail and clean corners
• High-gloss mould cavity finishing where polish-ready surfaces save hand time
• Small precision parts: watch components, connector details, medical pins
• Engraving, texturing and 3D contour work on hardened tooling

Choosing Between CM-870 and a VMC

If your parts need 12 mm depth cuts in steel with a 20 mm end mill, buy a machining centre. If your bottleneck is tiny cutters, long finishing programs and surface quality, the CM-870 pays for itself in reduced polishing and electrode rework. Many mould shops run both: a VMC for roughing plates and a CM-870 for detail work.

Footprint and Utilities

The machine occupies about 2400 x 2000 x 2600 mm and weighs 3800 kg, so it installs on a standard workshop floor. Total electrical capacity is 12 KVA, modest for the output. Tool capacity is 12 with random tool selection available as an option, enough for electrode jobs and finishing programs where tool counts stay low but changeovers are frequent.

Setup and Cutting Notes for Fine Work

Getting the best out of an engraving machine is mostly about discipline rather than force. Hold tools short: with ER32 or BT30 collets, run the stick-out as short as the part allows, because a long 3 mm cutter at 18000 rpm will whistle, wear and drift long before it breaks. Balance your finishing stock, leaving an even 0.1 to 0.2 mm for the final pass so the small tool loads consistently instead of biting into thick and thin areas.

Workholding matters more than on a heavy VMC. Copper electrodes and small mould details need clamping that does not distort them; think vacuum chucks, soft jaws and low clamping heights. Check coolant nozzles daily on detail work, since a dry corner on a graphite or copper electrode is where most scrapped parts start. None of this is complicated, but shops that set it up properly get polish-ready surfaces from the machine instead of extra bench hours.

Talk to VITOP Machinery

Planning a machine purchase or need help matching a model to your parts? Send your drawings or questions to vitopmachinery@163.com, or message us directly on WhatsApp: +86 183 1908 0212. You can also browse all machines at www.vitopmachinery.com. We reply within one business day.