DRMS Cordless

Drilling Resistance Measurement System

The DRMS Cordless (Drilling Resistance Measurement System) is a device designed to perform simple but precise drilling resistance measurements in stone materials and in mortars.

 

The system can measure continuously:

- Penetration force
- Actual drill position
- Rotational speed
- Penetration rate

Rotation speed and feedrate are constant during operation, and can be continuously regulated between min and max values.

 

The outputs of the system are numeric values and x-y plots of Drilling Force.

The equipment has been developed for laboratory tests and specially for outdoor application with integrated power battery to the unit for a good autonomy. Special diamond drill bits must be used to avoid wear effects.

Drill Bit Rotational Speed and Penetration Rate
The rotational speed (RS) of the drill ranges from 20 to 1000 rpm. The penetration rate ranges from 1 to 80 mm/min.
The rotational speed and penetration rate are controlled and maintained constant. This is realised by an appropriate electronic of actuation and control.
 

Drill Bit Position & Starting Point
The position of the drill, referred to the surface of the stone (starting point), is always known because it is controlled directly by the software through the dedicated electronics.

The hole depth measured by the system is exactly referred to the surface of target.

Force Measurement

The force applied to the target is measured continuously. The measurable force is comprised between 0 and 100 N.


ELECTRONIC FEATURES

Data Acquisition Board:
- USB port connection on IBM personal computers and compatibles running Windows 98® Operating System or higher
- 12 bit of resolution with PGA (Programmable Gain Amplifier).

Stepper and rotating motor control board:
- Programmable parametric values by RS232 connection
- Constant speed PWM control
- High output current (Max 8 A)
- Encoder to control speed and position.

Precision strain gage amplifier (Gain = 100).


SOFTWARE FEATURES

The acquired data are transmitted, during the test, to a PC through the USB serial data connection. The software, developed with LabVIEW™ (National Instruments), has many features related to the graphic data representation, loading and saving data files from the archive. Some important features are the following:

- Complete test management
- Graph of the force and torque against depth
- Mobile averaging of acquired data
- Possibility to show up to 6 test files together
- Possibility to calculate the average curve relative to different test
- Printing of calculated data
- Exporting data in text format
- Direct data input to the standard database.

Typical test results:

The following pictures show some typical results obtained during the drilling tests on different materials. In each case a diamond drill bit with a diameter of 5 mm was used.

 

Measured Drilling Force versus Depth on Monks Park Limestone

The sensitivity of the system and its capability to analyze every variation in the material are evident.

Measured Drilling Force
versus Depth on Carrara Marble (3 holes)

Correlation between
Ultimate Compressive Strenght and Drilling

 

DRMS with tablet PC

On site Measurement
Carrara Marble – Gioia Quarry