When a customer asks us for an ASTM D695 testing machine, we normally do not start by recommending a machine capacity.
We first ask about the specimen.
What material is it? How large is the loaded cross section? What compressive strength is expected? Does the laboratory need compressive strength only, or modulus as well?
These questions matter because two specimens tested under ASTM D695 can require very different equipment.
A small ABS specimen may generate only a few kilonewtons. A glass-fiber-reinforced engineering plastic with a larger cross section can exceed 10 or 20 kN. Some reinforced or composite specimens also introduce buckling and strain-measurement requirements that cannot be solved simply by installing larger compression platens.
The practical selection sequence is therefore:
Material → Specimen → Expected Load → Load Cell → Machine → Fixture → Measurement
This guide explains ASTM D695 from that equipment-selection perspective.
What Is ASTM D695?
ASTM D695 is a test method for determining the compressive properties of unreinforced and reinforced rigid plastics, including certain high-modulus composite materials.
As of August 2026, ASTM lists ASTM D695-26 as the active edition. The method covers specimens subjected to relatively low, uniform rates of straining or loading.
Depending on the material and test objective, results can include:
- Compressive Strength
- Compressive Modulus
- Yield Stress
- Deformation Beyond Yield
- Compressive Stress-Strain Behavior
One detail is important: not every plastic fails suddenly under compression.
Some materials yield and continue deforming or flattening. For materials without a distinct compressive failure, the reported compressive strength can depend on how the endpoint is defined.
For that reason, “We need ASTM D695” is not quite enough information to configure a testing system.
We also need to know what result the customer expects from the test.
How Does an ASTM D695 Compression Test Work?
For a conventional rigid plastic specimen, the principle is straightforward.
The specimen is positioned between suitable compression surfaces and loaded along its longitudinal axis. The universal testing machine applies compression at a controlled rate while recording force and deformation or strain.
A basic test chain looks like this:
Specimen
↓
Compression Fixture
↓
Controlled Axial Load
↓
Force + Deformation / Strain
↓
Stress-Strain Data
↓
Compressive Properties
The setup looks simple.
Getting good data is not always simple.
A specimen with poorly prepared ends can tilt. A thin specimen can buckle. Misaligned compression surfaces can introduce non-uniform loading. And if the load cell is poorly matched to the actual test force, buying a larger machine does not automatically improve the measurement.
That is why we treat the machine, load cell, specimen and fixture as one testing system.
Which Plastics and Products May Require ASTM D695 Testing?
ASTM D695 is fundamentally a material-property test, rather than a whole-product compression test.
For equipment selection, it is more useful to classify the application by material than by the finished product.
General Rigid Plastics
Typical materials can include:
ABS, PC, PA, POM, PMMA, rigid PVC and similar rigid polymers.
These materials may be found in:
- Consumer electronics housings
- Internal plastic structures
- Electrical components
- Appliance parts
- Plastic brackets
- Molded industrial components
When the specimen cross section is small and the material strength is moderate, the test force may remain within a 5 kN range.
This is where a low-force universal testing machine can make sense.
Engineering Plastics Change the Force Requirement
The selection becomes different with materials such as:
PEEK, PPS, reinforced PA, reinforced PBT and other structural engineering polymers.
They are commonly associated with applications such as:
- Automotive connectors
- Electrical insulation parts
- Sensor housings
- Structural plastic components
- High-temperature components
- Mechanical supports
A relatively small increase in specimen cross-sectional area or compressive strength can move the required load beyond 5 kN very quickly.
At that point, we would stop looking at a low-force machine and move into a higher-capacity platform.
Reinforced Plastics Require More Than a Larger Machine
Glass-fiber reinforcement adds another layer to the selection problem.
Examples include:
PA-GF, PBT-GF, GFRP and other reinforced polymer systems.
ASTM D695 covers reinforced rigid plastics and certain high-modulus composites within the scope defined by the standard.
For these specimens, we start looking more closely at:
- Maximum expected force
- Specimen thickness
- Slenderness and buckling risk
- End-face preparation
- Fixture design
- Strain measurement
So the quotation may change from:
Machine + Compression Fixture
to:
Machine + Appropriate Load Cell + Compression Fixture + Specimen Support + Strain Measurement
That distinction is important.
How Much Force Does an ASTM D695 Test Require?
This is the calculation we find most useful before selecting a machine.
A first estimate can be made using:
Estimated Compression Load = Compressive Stress × Loaded Cross-Sectional Area
Because:
1 MPa = 1 N/mm²
the calculation is straightforward when the material datasheet gives compressive stress in MPa and specimen dimensions are in millimeters.
Example 1: Small Rigid Plastic Specimen
Suppose:
Expected Compressive Stress = 50 MPa
Specimen Cross Section = 8 × 8 mm
Cross-sectional area:
8 × 8 = 64 mm²
Estimated force:
50 × 64 = 3,200 N
Therefore:
Estimated Maximum Load ≈ 3.2 kN
From force capacity alone, a 5 kN machine may be suitable.
We would still confirm the expected maximum stress, required measurement accuracy, safety margin and applicable specimen requirements before finalizing the configuration.
Example 2: Only the Specimen Changed
Now consider:
Expected Compressive Stress = 100 MPa
Specimen Cross Section = 10 × 10 mm
Area:
10 × 10 = 100 mm²
Estimated force:
100 × 100 = 10,000 N
Therefore:
Estimated Maximum Load ≈ 10 kN
A 5 kN machine is no longer appropriate.
Nothing happened to ASTM D695.
The standard stayed the same. The specimen changed. The machine requirement changed with it.
Why Machine Capacity Cannot Be Selected From “ASTM D695” Alone
Take the same 10 × 10 mm specimen cross section and change only the expected compressive stress:
| Expected Stress | Specimen Area | Estimated Load |
|---|---|---|
| 25 MPa | 100 mm² | 2.5 kN |
| 50 MPa | 100 mm² | 5 kN |
| 100 MPa | 100 mm² | 10 kN |
| 200 MPa | 100 mm² | 20 kN |
| 300 MPa | 100 mm² | 30 kN |
| 500 MPa | 100 mm² | 50 kN |
This is why a product page simply labeled “ASTM D695 Compression Tester” does not tell the buyer enough.
A more useful selection sequence is:
Compressive Stress × Loaded Area
↓
Expected Force
↓
Load Cell
↓
Machine Capacity
↓
Fixture
Three Typical ASTM D695 Selection Scenarios
The following are practical selection examples rather than claimed customer test cases.
Scenario A — ABS Material Testing
Suppose a laboratory is testing an ABS material specimen.
Specimen: 8 × 8 mm
Expected Compressive Stress: 55 MPa
Estimated force:
55 × 64 = 3,520 N
or approximately:
3.5 kN
A reasonable starting configuration would be:
【ANCHOR → RS-8010A】RS-8010A Universal Testing Machine
RS-8010A + Appropriate Load Cell + ITM-LAB Compression Fixture
With a 50 N–5 kN capacity range, the RS-8010A is the logical starting platform when the calculated test force remains within the low-kilonewton range.
There is little reason to start with a 50 kN machine when the expected force is around 3.5 kN.
Scenario B — Glass-Filled Automotive Engineering Plastic
Now consider a glass-filled PA specimen.
Specimen: 10 × 10 mm
Expected Compressive Stress: 180 MPa
Estimated force:
180 × 100 = 18,000 N
or:
18 kN
We have already moved far beyond the RS-8010A range.
The starting point becomes:
【ANCHOR → RS-8000】RS-8000 Universal Testing Machine
RS-8000 20 kN or higher + Appropriate Load Cell + Compression Fixture
The RS-8000 series, with 10–50 kN configurations, provides a more appropriate platform for engineering plastics and reinforced materials requiring higher compression loads.
The customer is still asking for ASTM D695.
But the equipment solution is completely different.
Scenario C — Reinforced Composite Specimen
Suppose the predicted test force is:
35–45 kN
and the specimen is relatively thin.
At this point, we would not simply quote:
50 kN machine + two platens.
We would first check:
- Will the specimen buckle?
- Is a support jig required?
- Is compressive modulus required?
- How will strain be measured?
- Is ASTM D695 actually the appropriate method, or should ASTM D3410/D3410M or ASTM D6641/D6641M be considered?
A possible starting platform is:
RS-8000 50 kN + Application-Specific Compression Fixture Review
This is a much better engineering conversation than simply asking whether the customer wants “a D695 machine.”
RS-8010A vs RS-8000 vs RS-8000A for ASTM D695
This is the section where buyers can translate their estimated force into an ITM-LAB machine platform.
RS-8010A — 50 N to 5 kN
Start here when testing:
- Small rigid plastic specimens
- Moderate-strength plastics
- Low-force material samples
- Plastics requiring tensile, flexural and compression testing on one platform
A typical configuration can be:
RS-8010A + Suitable Load Cell + ITM-LAB Compression Fixture
This is a good match when the calculated test force genuinely belongs in the low-kilonewton range.
Recommended for: General rigid plastics and small specimens where the expected load remains below the machine's usable capacity.
RS-8000 — 10 to 50 kN
Once the predicted force moves beyond 5 kN, we would normally start evaluating the RS-8000 range.
Typical applications can include:
- Engineering plastics
- Glass-filled polymers
- Reinforced plastics
- GFRP
- Larger specimen cross sections
- Higher-force multi-purpose material testing
Capacity can then be selected around the application rather than automatically choosing 50 kN.
For example:
≈ 8 kN expected load → evaluate 10 kN configuration
≈ 18 kN expected load → evaluate 20 kN or suitable higher configuration
≈ 40 kN expected load → evaluate 50 kN configuration
The final capacity should include an appropriate operating margin rather than matching the theoretical maximum exactly.
【ANCHOR → RS-8000A】RS-8000A High-Capacity Universal Testing Machine — 100 to 300 kN
We only move into a 100–300 kN platform when the test program actually needs it.
Examples can include:
- Test forces exceeding the lower-capacity platform
- Larger structural specimens
- High-force non-plastic tests performed on the same machine
- Laboratories consolidating multiple high-force applications
For a plastic specimen expected to generate 3 kN, a 300 kN frame is not automatically an upgrade.
It is simply a much larger machine than the test requires.
Machine Capacity and Load Cell Capacity Are Two Different Decisions
This is easy to overlook when comparing universal testing machines.
Suppose a laboratory purchases a 50 kN frame because it also performs higher-force tests.
That does not automatically mean every plastic specimen should be measured with the same 50 kN load cell.
For an ASTM D695 specimen producing only a few kilonewtons, the actual measurement range should still be considered when selecting the load cell.
So we separate two questions:
Can the machine safely generate the required force?
and:
Is the load cell appropriate for the force we actually want to measure?
A good testing system needs both answers.
What Compression Fixture Is Required?
For conventional rigid plastic specimens, the test can use an appropriate compression fixture with upper and lower loading surfaces.
ITM-LAB offers a dedicated Compression Fixture for universal testing machine configurations.
For ordinary rigid plastic specimens, the basic arrangement is:
Upper Compression Platen
↓
Plastic Specimen
↓
Lower Compression Platen
But we do not select the fixture only by looking at the word “compression.”
We also check:
- Specimen dimensions
- Contact area
- Alignment
- Parallelism
- Expected load
- Specimen stability
- Whether buckling is possible
A self-aligning loading arrangement can help accommodate small alignment differences, but it cannot correct a badly prepared specimen.
The specimen still needs to enter the test correctly.
What About Thin or Reinforced Specimens?
This is where the standard compression fixture may no longer be the whole solution.
Thin or high-modulus specimens can become unstable under axial compression.
Instead of measuring the intended material behavior, the specimen may buckle.
For certain reinforced/high-modulus ASTM D695 specimen configurations below 3.2 mm thickness, additional specimen support may be required to help prevent buckling.
That changes the setup from:
Compression Fixture
to potentially:
Compression Fixture + Support Jig
For this type of inquiry, we would ask for the specimen dimensions or drawing before confirming the fixture.
Why Specimen End Preparation Matters
ASTM D695 is an end-loading compression method.
The load enters through the ends of the specimen.
If those surfaces are not prepared correctly, one side can begin carrying load before the other.
The result can be:
- Tilting
- Uneven stress distribution
- Edge damage
- Premature failure
- Poor repeatability
- Abnormal stress-strain behavior
This becomes particularly important with reinforced and high-modulus materials.
If repeated specimens consistently deform first on the same side, alignment and specimen preparation are worth checking before blaming the sensor.
Do You Need an Extensometer for ASTM D695?
This depends on what you want to report.
There is an important difference between asking:
What is the maximum compressive strength?
and:
What is the compressive modulus?
If the Main Result Is Compressive Strength
The system primarily needs to capture the compression load and relevant deformation/failure behavior correctly.
A typical solution centers around:
Machine + Load Cell + Compression Fixture
If Compressive Modulus Is Required
Now strain measurement becomes much more important.
Modulus is derived from the slope of the stress-strain response in a defined region. Small strain-measurement errors can therefore have a noticeable effect on the result.
So before quotation, we would ask:
Do you need strength only, or strength + compressive modulus?
If modulus is required, the strain-measurement solution should be part of the equipment specification—not an afterthought.
ASTM D695 Is Not the Correct Standard for Every Plastic-Like Material
A good equipment supplier should also know when not to recommend D695.
Rigid Cellular Plastics
If the material is a rigid cellular plastic or foam, ASTM D1621 should be considered rather than treating it as an ordinary D695 rigid plastic specimen.
Certain Advanced Composites
ASTM D695 is also not automatically the preferred method for every continuous-fiber composite.
Depending on reinforcement architecture and the required test method, standards such as:
ASTM D3410/D3410M
or
ASTM D6641/D6641M
may be more appropriate.
This is why the first question remains:
What material are you actually testing?
ASTM D695 vs ISO 604
ASTM D695 and ISO 604 both address compressive testing of plastics.
For laboratories supplying multiple international markets, a universal testing platform capable of supporting both ASTM- and ISO-based plastic compression methods can therefore be useful.
However, laboratories should configure the actual test according to the specified standard rather than mixing test parameters between methods.
One Testing Platform for ASTM D638, ASTM D790 and ASTM D695
This is where a universal testing machine can become more valuable than a single-purpose compression tester.
A plastics laboratory commonly needs more than one mechanical property.
| Standard | Test | ITM-LAB Fixture |
|---|---|---|
| ASTM D638 | Tensile | Tensile Fixture |
| ASTM D790 | 3-Point Flexural | Bending Fixture |
| ASTM D695 | Compression | Compression Fixture |
These are three different tests.
They do not necessarily require three different machines.
With the correct capacity, load cell, software method and fixtures, one universal testing platform can be configured for:
Tensile + Flexural + Compression
For a low-force plastics laboratory, this can mean:
RS-8010A + Tensile Fixture + Bending Fixture + Compression Fixture
For engineering and reinforced plastics requiring greater force:
RS-8000 + Application-Specific Load Cell + Required Fixtures
This is a more useful way to plan a plastics laboratory than purchasing equipment one standard at a time.
Before We Recommend an ASTM D695 Machine
For a new inquiry, these are the questions we would want answered:
1. Material
ABS, PC, PA, POM, PEEK, PA-GF, GFRP or another material?
2. Specimen Dimensions
Especially the loaded cross-sectional dimensions.
3. Expected Compressive Strength
An approximate value from the material datasheet is already useful.
4. Expected Maximum Force
If unknown, it can be estimated from stress and specimen area.
5. Required Result
Strength? Yield? Modulus? Full stress-strain curve?
6. Specimen Stability
Is the specimen thin or likely to buckle?
7. Required Standard
ASTM D695? ISO 604? Customer-specific method?
8. Other Tests
Will the same machine also perform ASTM D638 tensile or ASTM D790 flexural testing?
With these answers, the equipment discussion becomes much more specific.
Common ASTM D695 Equipment Selection Mistakes
Selecting by Standard Number Alone
ASTM D695 tells us the test method.
It does not tell us whether the customer needs 5 kN or 50 kN.
Assuming All Plastic Compression Tests Are Low Force
A small change in material strength or specimen area can multiply the required load.
Choosing the Largest Machine “To Be Safe”
More capacity is not automatically better for a low-force test.
Ignoring Load Cell Selection
Frame capacity and measurement range are related, but they are not the same specification.
Using the Same Fixture for Every Specimen
Thin and reinforced specimens may introduce buckling and require additional support.
Asking About Strength but Forgetting Modulus
If modulus is required, strain measurement becomes part of the system specification.
Assuming Every Composite Uses ASTM D695
The reinforcement architecture and specimen configuration may point toward another compression method.
FAQ
What does ASTM D695 measure?
ASTM D695 is used to determine compressive properties of unreinforced and reinforced rigid plastics and certain high-modulus composite materials. Results can include compressive strength, modulus, yield stress and deformation behavior.
Is a 5 kN machine enough for ASTM D695?
Sometimes.
For example, a specimen with an 8 × 8 mm loaded area and an expected compressive stress of 50 MPa produces an estimated load of approximately 3.2 kN.
A stronger material or larger specimen can easily exceed 5 kN.
How do I estimate ASTM D695 test force?
As an initial equipment-selection estimate:
Estimated Load = Expected Compressive Stress × Loaded Cross-Sectional Area
For MPa and mm², the resulting force is in newtons.
Can ASTM D695 require 20 or 50 kN?
Yes.
Engineering plastics, reinforced materials and larger cross sections can move the required force into 10, 20, 50 kN or higher ranges.
Which ITM-LAB machine is suitable for ASTM D695?
For lower-force specimens, the RS-8010A 50 N–5 kN can be considered.
For engineering and reinforced plastics requiring greater force, the RS-8000 10–50 kN range is generally the more appropriate starting point.
The RS-8000A 100–300 kN should be considered only when the actual force or wider laboratory test program justifies the higher capacity.
What fixture is required?
Conventional rigid plastic specimens can use an appropriate compression fixture.
Thin or reinforced specimens may require additional specimen support or anti-buckling arrangements.
Do I need an extensometer?
If compressive modulus is required, strain measurement should be specifically considered.
Strength-only and modulus testing should not automatically be treated as identical equipment configurations.
Can one machine perform ASTM D638, D790 and D695?
Yes, if machine capacity and measurement requirements are suitable.
The main fixture configurations become:
Tensile Fixture → ASTM D638
Bending Fixture → ASTM D790
Compression Fixture → ASTM D695
Is ASTM D695 used for foam?
Rigid cellular plastics generally require a different compression method, such as ASTM D1621, rather than being treated as conventional ASTM D695 specimens.
Final Selection Rule: Start With the Specimen
The most important point in ASTM D695 equipment selection can be summarized in one sentence:
The ASTM standard defines the test method. The specimen defines the force requirement.
For a small conventional rigid plastic specimen, the correct solution may be:
RS-8010A + Load Cell + ITM-LAB Compression Fixture
For a stronger engineering plastic:
RS-8000 + Appropriate Load Cell + ITM-LAB Compression Fixture
For reinforced or thin specimens:
RS-8000 + Compression Fixture + Specimen Support + Appropriate Strain Measurement
And if the expected force genuinely exceeds those ranges, only then should a higher-capacity RS-8000A platform be considered.
The objective is not to put every ASTM D695 specimen on the largest available universal testing machine.
It is to configure the machine, sensor, fixture and specimen so that they work in the right range together.
