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Introduction: This guide checks whether a specific mold plate, insert, or cavity block fits the VMC855's 800 / 550 / 550 mm travel, 1000 × 550 mm table, 500 kg load, BT40 spindle, and 24-station magazine before a shop commits to a quotation.
A mold shop's real question is whether a specific plate, insert, or cavity block fits the VMC855 envelope, table, and tooling before anyone quotes a price. Most machine evaluations start with a drawing, not a spec sheet. A mold base plate, a cavity insert, or a fixture plate has a length, width, height, and weight, and the machine either takes that package or it does not. The VMC855 is a 3-axis vertical machining center with 800 / 550 / 550 mm of X, Y, and Z travel, a 1000 × 550 mm table rated for 500 kg, a BT40 spindle running to 8000 rpm on a belt drive, and a 24-station disc magazine. The practical sequence is envelope first, then table and clamping, then spindle, tool magazine, and the configuration details the supplier is worth checking. That sequence tells a mold shop whether this machine belongs in the quotation.
The check that decides the answer is whether the cutter reaches every feature on the part. X travel of 800 mm, Y travel of 550 mm, and Z travel of 550 mm describe tool-center movement, not maximum part size. A cutter has to clear the edge of a plate before it can face it, so practical part size is travel minus cutter diameter and approach room on each side. A 700 × 450 mm mold base plate fits comfortably in X and Y. A 780 × 530 mm plate leaves almost nothing spare and usually forces repositioning partway through the cycle, adding setup time and another chance for a location error. Height and depth close in faster than many drawings suggest. Spindle nose to table distance runs from 120 mm to 670 mm, and the spindle center sits 590 mm from the column guideway. For a 250 mm tall cavity insert standing on a 200 mm angle plate, the top face is already at 450 mm, leaving roughly 220 mm above it for the tool, holder, and clearance. That is workable for normal finishing tools and tight for long-reach cutters. The 590 mm dimension works the same way on the Y side: part and clamping both have to sit inside the space between the spindle axis and the column. Nominal positioning accuracy is ±0.004 mm and repeat positioning accuracy is ±0.003 mm, the class of machine mold shops normally expect for hole positions, parting lines, and cavity walls. Those figures describe the machine. The tolerance on the finished part still depends on fixture, cutter, and machining strategy, which is why the next check is the table rather than the accuracy line.
The table measures 1000 × 550 mm with five 18 mm T-slots on 90 mm pitch. The table is 200 mm longer than the X travel, which gives room for staging clamps and tools, but the cutting area remains tied to X travel. A workpiece longer than roughly 800 mm still needs a repositioning setup or a larger machine. The 90 mm T-slot pitch decides how clamps land, so lay your hole pattern over it before committing. Straps and step clamps need slot positions that do not sit on top of a cavity or a bolt hole you still have to drill. The 500 kg table load covers the workpiece and everything holding it. A 380 kg mold plate on a 90 kg fixture plate lands at 470 kg and stays inside the limit. A 450 kg plate on an 80 kg angle plate lands at 530 kg and exceeds it. That is the practical difference between a plate that runs as one setup and a plate that must be split into two setups or moved to a bigger machine. Weigh the fixture, clamps, and parallels along with the steel you are cutting, and do it before the inquiry rather than after the order. Standard mold shop clamping—machine vises, angle plates, step clamps, and clamping kits—mounts onto these T-slots, and BT40 tool holders match the spindle taper. If the fixture plate is heavier than you first estimated, say so early: it changes the configuration, not just the final price.
The spindle is a BT40 belt drive rated to 8000 rpm with an 11 / 15 kW motor, and the magazine holds 24 tools with a maximum tool weight of 8 kg. Mold work is tool-hungry: a face mill for the base, several indexable cutters for roughing the cavity, small ball nose tools for finishing, plus drills, taps, and reamers. A full set easily runs past a dozen stations, and 24 positions let you leave that set loaded instead of swapping tools between operations. Four configuration points usually need supplier confirmation.
Attach the drawing, the fixture weight, and your controller preference to the inquiry, and the quotation can come back as a configuration rather than a list of numbers. When you compare one vertical machining center supplier against another, the difference usually shows up in exactly those answers.
The VMC855 fits mold shops whose parts stay inside an 800 × 550 × 550 mm envelope, whose workpiece and fixture together stay under 500 kg, and whose part height plus fixture stays workable within the 120–670 mm spindle nose range. Inside those limits, it covers a full mold workflow—roughing, finishing, drilling, tapping, and boring—with a 24-station magazine that keeps the tool set loaded and a BT40 spindle that reaches 8000 rpm. Before requesting a quotation, put the drawing, fixture weight, and controller preference in front of someone who can confirm the controller, guideway, tool length, and shipping figures. SENMO is a CNC machining center manufacturer in Qingzhou, China, and the team can check your workpiece against the VMC855 specification and quote the configuration you need.
A：Treat 800 x 550 x 550 mm as tool-center movement rather than part size. A plate around 700 x 450 mm fits comfortably in X and Y, while a plate near 780 x 530 mm needs a repositioning setup. Vertically, the spindle nose reaches from 120 mm to 670 mm above the table, so part height plus fixture plus tool and holder must fit inside that band.
A：The 500 kg rating covers the workpiece and fixture together, so a 500 kg plate plus clamps and parallels goes over the limit. A 380 kg plate on a 90 kg fixture plate sits at 470 kg and stays inside it, and that is the calculation to run before ordering. If the combined weight lands above 500 kg, plan a lighter fixture setup or a larger machine.
A：Confirm four things with the supplier: the CNC controller brand and version, the guideway type on X, Y, and Z, the maximum tool length the magazine accepts, and the machine footprint and weight for shipping. Those four items drive integration, maintenance planning, tooling reach for deep cavities, and delivery arrangements. Put them in the inquiry rather than relying on a general specification table.
Methods for Performance Evaluation of Computer Numerically Controlled Machining Centers - ASME
Lecture Notes | Design and Manufacturing I | Mechanical Engineering | MIT OpenCourseWare
VMC855 Vertical Machining Center
