What should be paid attention to when high-precision engraving machine is used to process fiber bottom die?

I'll give you a set of notes that can be used directly on site, especially for fiber bottom die (FRP/carbon fiber/composite die) and high-precision engraving machine. They are all key points of the process, so don't be wordy and land directly:

A, machine tools and preparation before processing

Machine tool accuracy inspection

Spindle radial runout, guide rail clearance and screw clearance must be re-measured, with an error of ≤ 0.02mm..

The flatness of the table top and the parallelism of the fixture should be calibrated to avoid warping and steps of the mold surface.

Confirmation of bottom die material

The hardness of wood substitute, resin substitute, PU model material, gypsum, epoxy resin plate, etc. should be uniform.

Materials with impurities, soft spots and layers can't be used, which will cause edge collapse, broken knives and affect the finish.

Clamping and fixing

It must be pressed evenly in a large area, and it is not allowed to press hard at a single point to prevent material deformation and knife bounce.

Large-size molds must be supported by multiple points and positioned laterally to prevent displacement during processing.

Second, the tool selection (fiber bottom die is the most critical)

Tool type

Rough machining: single/double-edged spiral milling cutter with good chip removal and high efficiency.

Finishing: mirror milling cutter, ball cutter and single-edged high-gloss cutter to ensure smooth surface.

It is forbidden to use worn and chipped tools, which may cause shock lines, galling and step lines.

Tool path

Finish milling as far as possible to reduce burr and edge collapse.

The R-angle and curved surface of the die shall be milled in layers with small step spacing, and the step spacing is generally ≤ 0.1 mm..

III. Cutting parameters (directly copied)

Rough machining:

Rotating speed is 12000–18000 r/min.

Feed 3000–6000 mm/min

The cutting depth is controlled according to the hardness of the material.

Finishing:

Rotating speed is 18,000–24,000 r/min.

Feed 1000–3000mm/min.

The cutting depth is 0.1-0.3mm

Principle: high speed, small cutting depth and moderate feed to ensure smoothness and accuracy.

Iv. Key points of processing technology

Separation of coarse and fine machining

Leave 0.3–0.8 mm finishing allowance for rough machining, and don't put it in place at one time.

Finishing and molding at one time, to avoid repeated tool repair resulting in tool joint marks.

Curved surface, parting surface, R angle

The parting surface must be rooted in place, otherwise the gap of closing the mold will be large in the later stage.

Deep cavity and narrow groove should be coarsened first, and then the angle should be cleared to prevent the knife from being broken and bounced.

Avoid shock lines and knife lines

The shorter the extension length of the cutter, the better.

The acceleration and deceleration of the machine tool should not be too large, and the surface processing will reduce the acceleration.

Five, cooling and chip removal (die surface quality key)

Substitute wood and resin are generally dry-cut, and must be strongly vacuumed.

Dust can't enter the guide rail, screw and spindle, otherwise the precision will be scrapped quickly.

It is forbidden to cut chips twice, which will scratch the surface of the mold.

Six, size and precision control

Before machining, it is necessary to check the centering and alignment of knives, and it is best to use edge finder+centering rod.

Measure the size in the middle of the large mold to prevent deviation and waste parts.

Generally, the tolerance of the mold is required to be ±0.02~±0.05mm, and the key surfaces should be fully programmed.

VII. Post-treatment and protection

Don't pry or knock hard after machining to avoid deformation and corner collapse of the bottom die.

Slight knife marks can be lightly polished with fine sandpaper and polishing wheel, so as not to damage the profile accuracy.

Make a good mark to avoid bumping and scratching-the fiber bottom die will be scrapped as soon as it is scraped.

VIII. Safety and Maintenance

Spindle preheating, lubrication and normal reprocessing.

Do not observe the cutting tool at close range and operate the rotating parts without gloves.

After completion, clean the guide rail, rack and screw of the machine tool to prolong the high-precision life.