PENTA Series Hand & Belt Grinders
The PENTA Series features hand grinders with silicon carbide rolls for precision material removal. Perfect for use with lapping films and achieving fine surface finishes.
Key Considerations
Select Appropriate Film Type
Use alumina for intermediate steps and softer materials; diamond films for harder, brittle, or high-precision applications requiring superior flatness.
Use Controlled Pressure
Even, light pressure enhances uniformity and prevents localized wear, ensuring consistent surface finishes across the entire sample.
Keep Surfaces Clean
Clean substrates and film before use to maximize performance and avoid scratching that can compromise sample quality.
Introduction
Lapping films are precision-coated abrasives that produce extremely flat surfaces across diverse materials. They're ideal for semiconductor dies, fiber optics, ceramic capacitors, optical components, and hard drive read-write heads.
These films feature a durable polyester backing (typically 3 mils) with abrasives fixed using an epoxy or adhesive binder. The uniform abrasive distribution ensures consistent surface finishes, even across varying material hardnesses.
Film Types
- Diamond lapping films: The hardest abrasive option, ideal for hard or brittle materials such as ceramics, silicon, hardened steels, and optical components. Produce less surface relief than diamond suspensions on cloth because the abrasive is fixed, which is why they are widely used for TEM and SEM specimen preparation.
- Silicon carbide lapping films: A cost-effective precision lapping option, particularly well-suited to glass, silica, fiber optic ferrules (ceramic and zirconia), and silicon. SiC films provide a slightly more aggressive cut at equivalent micron sizes than alumina, with predictable wear behavior that supports consistent precision lapping.
- Alumina lapping films: The gentlest of the three abrasive types, recommended for soft or ductile metals where diamond would embed, and as a final-stage flat-polishing abrasive across many material families including metals, ceramics, glass, and electronic packages. Particularly useful when edge retention and minimal embedding are critical.
Backing Types
- Plain-backed: Require a wet plate surface for water-tension adhesion. The film sits directly on the rigid plate with no compliant layer, giving the best flatness and edge retention. Use plain-backed films for precision applications, hard/soft interfaces (coatings, case-hardened layers), and fiber optic endface work where edge rounding is unacceptable.
- PSA-backed: Self-adhesive for quick installation. The adhesive layer adds a small amount of compliance between the film and the plate, which improves convenience but can cause edge rounding and relief on hard/soft interfaces (see Troubleshooting). Use PSA-backed films when convenience outweighs maximum flatness, or for routine metallographic prep where minor edge effects are acceptable.
Recommended Procedures
Follow these procedures to achieve optimal results with lapping films. The process varies slightly depending on backing type and application requirements.
For Plain-Backed Lapping Films
- Wet the flat lap plate with water or a water/surfactant solution
- Place the plain-backed lapping film on the surface
- Roll out or press out any entrapped air bubbles to ensure full contact
- Apply necessary lubricant (water, diamond lapping film lube, or appropriate polishing fluid)
- Begin polishing with light force, typically 2-5 lbs per specimen (≈9-22 N per specimen), to avoid tearing the film. Start at the lower end and increase only if removal is insufficient.
- Use complementary (matched) rotation: head and platen in the same direction at matched speeds. Typical settings: 60-120 RPM for fine films (≤9 µm), 100-150 RPM for coarse films (15-30 µm).
- Clean specimen and film for the final 10-15 seconds of the polishing cycle
- Clean and dry specimens thoroughly before proceeding to the next step
For PSA-Backed Lapping Films
- Ensure the lapping plate surface is clean and dry
- Place the PSA-backed lapping film on the surface, pressing firmly from center outward
- Apply necessary lubricant (water, diamond lapping film lube, or appropriate polishing fluid)
- Begin polishing with light force, typically 2-5 lbs per specimen (≈9-22 N per specimen), to avoid tearing the film. Start at the lower end and increase only if removal is insufficient.
- Use complementary (matched) rotation: head and platen in the same direction at matched speeds. Typical settings: 60-120 RPM for fine films (≤9 µm), 100-150 RPM for coarse films (15-30 µm).
- Clean specimen and film for the final 10-15 seconds of the polishing cycle
- Clean and dry specimens thoroughly before proceeding to the next step
Process Parameters
Typical process parameters for lapping films:
- Force: 2-5 lbs per specimen (≈9-22 N per specimen). Start at the lower end and increase only if removal is insufficient. For central-load heads, multiply by the number of specimens in the holder.
- Speed: Complementary (matched) rotation, same direction. 60-120 RPM for fine films (≤9 µm); 100-150 RPM for coarse films (15-30 µm). Avoid true counter-rotation (head and platen in opposite directions), which produces uneven film wear.
- Time: Continue until the surface is planar and the previous step's scratches are fully removed. Typical step durations range from 30-90 seconds per micron of stock to remove.
- Lubrication: Maintain adequate lubricant flow to prevent swarf buildup and film damage
Diamond Lapping Films
| Description | Size (inches) | Catalog Number (Plain-backed) | Catalog Number (PSA backed) | Color Code |
|---|---|---|---|---|
| 0.10 um Diamond Lapping Film | Up to 12-inches | DA-01 | DAA-01 |  |
| 0.25 um Diamond Lapping Film | Up to 12-inches | DA-025 | DAA-025 |  |
| 0.50 um Diamond Lapping Film | Up to 12-inches | DA-05 | DAA-05 | |
| 1 um Diamond Lapping Film | Up to 12-inches | DA-1 | DAA-1 |  |
| 3 um Diamond Lapping Film | Up to 12-inches | DA-3 | DAA-3 |  |
| 6 um Diamond Lapping Film | Up to 12-inches | DA-6 | DAA-6 |  |
| 9 um Diamond Lapping Film | Up to 12-inches | DA-9 | DAA-9 |  |
| 15 um Diamond Lapping Film | Up to 12-inches | DA-15 | DAA-15 |  |
| 30 um Diamond Lapping Film | Up to 12-inches | DA-30 | DAA-30 |  |
Diamond Lapping Film Lubricants
| Description | Quantity (oz) | Catalog Number |
|---|---|---|
| 32 oz Diamond Lapping Film Lube | 32 | LFL-032 |
| 1 gallon Diamond Lapping Film Lube | 128 | LFL-128 |
Silicon Carbide Lapping Films
| Description | Size (inches) | Catalog Number (Plain-backed) | Catalog Number (PSA backed) |
|---|---|---|---|
| 1.0 um silicon carbide | Up to 12-inches | SIC-001PB-3 | SIC-001PSA-3 |
| 3.0 um silicon carbide | Up to 12-inches | SIC-003PB-3 | SIC-003PSA-3 |
| 5.0 um silicon carbide | Up to 12-inches | SIC-005PB-3 | SIC-005PSA-3 |
| 9.0 um silicon carbide | Up to 12-inches | SIC-009PB-3 | SIC-009PSA-3 |
| 12 um silicon carbide | Up to 12-inches | SIC-012PB-3 | SIC-012PSA-3 |
| 20 um silicon carbide | Up to 12-inches | SIC-020PB-3 | SIC-020PSA-3 |
| 30 um silicon carbide | Up to 12-inches | SIC-030PB-3 | SIC-030PSA-3 |
Alumina Lapping Films
| Description | Size (inches) | Catalog Number (Plain-backed) | Catalog Number (PSA backed) | Color Code |
|---|---|---|---|---|
| 0.05 um alumina (ALO) | Up to 12-inches | ALO-105PB-3 | ALO-105PSA-3 |  |
| 0.30 um alumina | Up to 12-inches | AL-103PB-3 | AL-103PSA-3 | |
| 1.0 um alumina | Up to 12-inches | AL-001PB-3 | AL-001PSA-3 |  |
| 3.0 um alumina | Up to 12-inches | AL-003PB-3 | AL-003PSA-3 |  |
| 5.0 um alumina | Up to 12-inches | AL-005PB-3 | AL-005PSA-3 |  |
| 9.0 um alumina | Up to 12-inches | AL-009PB-3 | AL-009PSA-3 |  |
| 12 um alumina | Up to 12-inches | AL-012PB-3 | AL-012PSA-3 |  |
| 15 um alumina | Up to 12-inches | AL-015PB-3 | AL-015PSA-3 |  |
| 30 um alumina | Up to 12-inches | AL-030PB-3 | AL-030PSA-3 |  |
Troubleshooting
| Symptom | Cause | Action |
|---|---|---|
| Coarse scratching | -Swarf build-up on the lapping film | -Use a lubricant with an appropriate surfactant |
| Tearing of pad | -Sharp specimen edges | -Reduce initial applied load so that the specimen edge does not cut the film. Gradually increase pressure during the lapping operation. -Dispense lubricant more frequently |
| Excessive relief or edge rounding | -PSA backing providing too much flexibility (resiliency) -Lapping backing plate surface is not flat |
-Use a plain backed diamond lapping film -Use a flat lapping surface |
Related Equipment
NFZ System (NANO-FEMTO-ZETA-RC)
Complete automated grinding and polishing workflow with precise control for lapping film applications and final finishing steps.
Frequently Asked Questions
Common questions about lapping films
What's the difference between diamond, SiC, and alumina lapping films?
Diamond lapping films provide the finest finish on the hardest materials (ceramics, silicon, hardened steels, optical components) and are widely used for TEM and SEM specimen preparation because their fixed abrasive produces less surface relief than diamond on cloth. Silicon carbide (SiC) films are a cost-effective precision option, especially strong on glass, silica, fiber optic ferrules, and silicon, with a slightly more aggressive cut at equivalent micron sizes than alumina. Alumina films are the gentlest option, recommended for soft or ductile metals where diamond would embed, and as a final-stage flat-polishing abrasive when edge retention matters. Choose based on material, edge-retention needs, and cost.
Should I use plain-backed or PSA-backed lapping films?
Plain-backed films use water-tension adhesion to sit directly on a rigid lapping plate, with no compliant layer between the film and the plate. This produces the best flatness and edge retention, making plain-backed the right choice for precision applications, hard/soft interfaces (coatings, case-hardened layers), and fiber optic endfaces. PSA (pressure-sensitive adhesive) backed films self-adhere to the plate for fast installation, but the adhesive layer adds a small amount of compliance that can cause edge rounding and relief on samples with hard/soft transitions. Use PSA when convenience matters more than maximum flatness; use plain-backed when edge retention is critical.
What grit sequence should I use for lapping films?
Start with the coarsest grit needed for your starting condition (typically 15-30 µm if coming off a saw cut, or 9 µm if starting from a pre-ground surface), then progress through finer grits. Unlike grinding papers, lapping films are often used with step-skipping sequences because the damage per step at fine sizes is small. Common sequences include 30 → 9 → 3 → 1 → 0.3 µm for fiber optics and 9 → 3 → 1 → 0.05 µm for metallography. The key is to verify that each step fully removes the prior step's scratches before progressing, regardless of whether intermediate steps are used.
How do I prevent film tearing during use?
Film tearing typically results from excessive pressure, insufficient lubrication, or debris on the polishing surface. To prevent tearing: 1) Use light, consistent pressure (2-5 lbs / 9-22 N per specimen), 2) Ensure adequate water or lubricant flow, 3) Clean the backing plate thoroughly before applying new film, 4) Inspect specimens for sharp edges that can catch the film, and 5) Replace worn films promptly before they tear.
Can I use lapping films without lubrication?
Lubrication is essential for lapping films. Water is the most common lubricant, providing cooling, swarf removal, and film protection. Using films dry will cause rapid film degradation, excessive heat generation, specimen damage, and poor surface finish. Always use adequate lubrication, typically water for most applications, though some materials may require specialized lubricants to prevent corrosion or chemical reactions.
How do I know when to replace a lapping film?
Replace lapping films when you notice: 1) Reduced cutting efficiency requiring longer polishing times, 2) Visible wear patterns or bald spots on the film surface, 3) Inconsistent scratch patterns on specimens, 4) The film becoming discolored or loaded with swarf that won't rinse away, or 5) Any tears or delamination. Regular replacement ensures consistent results and prevents specimen damage from worn films.