How to choose a high-precision engraving machine suitable for processing fiber bottom die?

The core of the high-precision engraving machine for selecting fiber bottom die (wood substitute, epoxy resin and PU model material) is six items: rigidity, accuracy, spindle, transmission, dust removal and software, which can be directly selected according to the following standards.

First, determine the core requirements (selection premise)

Processing material: substitute wood/epoxy resin/PU/gypsum (hardness, density, easy edge collapse)

Die size: maximum length, width and height → determine X/Y/Z stroke.

Accuracy requirements: the bottom die is usually ±0.02~±0.05mm, and the mirror surface/high gloss surface should be higher.

Capacity: single piece/batch, whether it runs 24 hours?

Budget range: entry/mid-range/high-end (determine configuration and brand)

Second, the mechanical structure (stability foundation, the highest weight)

1. The fuselage material and rigidity (must see)

First choice: integral gantry gray cast iron/nodular cast iron (aging treatment), the greater the dead weight, the better (≥ 1.5t/m stroke).

It is forbidden to: aluminum profile splicing and square pipe welding (easy to shake and deform, and the accuracy is not guaranteed).

Key points: the beam, the lathe bed and the upright post are integrally cast, and there is no splicing weld, so it has strong vibration resistance.

2. Guide rail and slider (moving smoothly)

Standard: precision linear guide rail (HIWIN/THK/PMI), heavy-duty type.

Requirements: Pre-tightening of guide rail, number of sliders ≥4/shaft, no gap and low friction.

3. Transmission system (precision core)

X/Y/Z axis: grinding ball screw+double nut pre-tightening (T-shaped screw and rack are rejected)

Coupling: high rigidity diaphragm coupling, no gap.

Drive: Bus servo motor (Panasonic/Mitsubishi/An Chuan/Delta), stepping motor is rejected.

Repeated positioning accuracy: ≤±0.01mm；; Positioning accuracy ≤±0.02mm

Three, the spindle system (processing quality heart)

1. Spindle type and power

First choice: water-cooled high-speed motorized spindle (good heat dissipation, long life and small vibration)

Power: 3.0~7.5kW (for wood/epoxy hard materials ≥5.5kW)

Maximum rotating speed: 24000~40000rpm (finishing needs ≥ 30,000 rpm).

Runout: radial runout of spindle ≤0.002mm (at the handle)

2. Tool holder and tool change (efficiency)

Handle: ER32/ER40/BT30 (good rigidity and high tool loading accuracy)

Automatic tool change: required for batch/multi-process (tool magazine capacity ≥8).

Four, precision and control (the key to the success or failure of the bottom die)

1. Accuracy index (must meet the standard)

Repeated positioning: ≤±0.01mm

Positioning accuracy: ≤±0.02mm

Flatness/verticality: ≤0.02mm/m

Clearance between lead screw and guide rail: ≤0.005mm (after pre-tightening)

2. Control system (stable+easy to use)

Mainstream: new generation SYNTEC, Baoyuan LNC, Weihong NK300, Fanuc (bus closed loop)

Function:

Support high-speed and high-precision mode (HSM) and forward-looking pretreatment (≥2000 segments)

Tool compensation, radius compensation, spiral interpolation, five-axis linkage (complex surface)

Power-off memory, breakpoint carving, overload protection

V. Dust removal and protection (exclusive to fiber bottom die)

Strong dust suction: spindle side blowing+table top suction, negative pressure ≥3kPa, to prevent dust from entering the guide rail/screw/motor.

Sealing: X/Y/Z axis fully enclosed shield, organ cover, waterproof and dustproof.

Cooling: dry cutting is the main method, and micro lubrication (MQL) is optional to avoid water absorption and deformation of materials.

Six, stroke and table (to adapt to the size of the mold)

Stroke: X/Y is 200~300mm larger than the maximum die size, and Z axis ≥ die thickness+cutter+safety margin (≥200mm).

Table top: T-groove cast iron table top (flatness ≤0.02mm/m), multi-point compaction and convenient clamping.

Seven, according to the budget and scene selection (direct comparison)

1. Entry-level (budget ≤ 200,000, single small mold)

Configuration: cast iron gantry, servo+ball screw, 3.0kW/24000rpm water-cooled spindle, new generation/Victoria macro system.

Application: small wooden model with accuracy of ±0.05mm and small batch.

2. Mid-range mainstream (budget 200,000 ~ 500,000, mass production/high precision)

Configuration: integral casting, heavy-duty guide rail, 5.5kW/30000rpm, automatic tool change, closed-loop servo, full dust prevention.

Application: medium-sized bottom die, ±0.02~±0.03mm, 24-hour operation.

3. High-end precision (budget ≥ 500,000, mirror/highlight/large)

Configuration: mineral casting/high rigidity cast iron, 6~7.5kW/40000rpm, BT30 tool magazine, five-axis linkage and constant temperature control.

Application: large/complex curved surface, ±0.01mm, carbon fiber/glass fiber reinforced plastic high gloss mold.

Eight, choose to avoid pit (must see)

Just look at the parameters and don't look at the rigidity and self-weight (no matter how high the precision of the light fuselage is, it's no use)

Using stepping motor+common screw as high precision (easy to lose step and large gap)

Insufficient spindle speed/power (easy edge collapse, vibration, poor finish)

No strong dust removal (dust destroys the guide rail and the precision drops rapidly)

The control system has no high-speed foresight (complex surfaces are prone to shaking and knife marks)

Nine, on-site acceptance points (must be measured before buying)

Run idle for 30 minutes, and measure vibration, noise and temperature rise.

Repetitive positioning, positioning accuracy and flatness are measured by meter.

Try to cut the substitute wood/epoxy parts, and measure the smoothness, R angle, dimensional tolerance and edge collapse.

Run it continuously for 8 hours to see whether it is stable, out of step and hot.